US2205019A - Miter box - Google Patents

Description

June 18, 1940. P NS v 2,205,019

' MITER BOX Filed May 11, 1937 4 Sheets-Sheet 1 IN V EN TOR.

' r By MN m ma June 18, 1940. v w. J. PARSONS 2,205,019 MITER BOX Filed May 11, 1957 4 Sheets-Sheet 2 IN V EN TOR.

ATTOR June 18, 1940. w P SONS 2,205,019

MITER BOX Filed May 11, 1937 4 Sheets-Sheet 3 FRAMf 1N VEN TOR.

' A TTORNE Patented June 1 8, 1940 UNlTED STATES MITER BOX William J. Parsons, Millers Falls, Mass, assignor to Millers Falls Company, Greenfield, Mass, a corporation of Massachusetts Application May 11, 1937, Serial No. 141,884

4 C lairnsf (Cl. 143-86) The present invention provides certain improvements in the construction of miter boxes. More particularly, the present invention provides an improved and simplified construction of clamping instrumentalities for stock to be sawed and means for mounting such instrumentalities whereby the clamping and. releasing of the stock is greatly facilitated, together with improved construction of the saw guides. 10 In accordance with the present construction,

clamping means for the stock to be sawed are provided, which clamping means are quickly adjustable and which are carried in novelly shaped and novelly mounted brackets which facilitate the quick adjustment of the clamping means;

and one of the objects of the invention is to provide such brackets which are mounted in such a manner that they may be shifted freely and very easily between operative and inoperative positions.

A further object of the invention is to provide locking means for the brackets, which locking means are self-actuating responsively to the brackets assuming operative position, so as to secure the brackets in such position while being instantaneously releasable for enabling the brackets to be released for adjustment or other desired purpose. I

A still further object of the invention is to provide mounting means for the brackets for enabling adjustment of the brackets longitudinally of the base support for accommodating the clamping instrumentalities to any length of stock which is to be cut. v

A still further object of the invention is to provide clamping instrumentalities for the stock, which instrumentalities are pivotally mounted in the said brackets and which are adapted to either a quick or slow adjustment selectively relative to the stock.

A still further object of the invention is to provide mechanism for mounting the said clamping instrumentalities in the brackets while permitting the aforesaid quick or slow adjustment of the clamping instrumentalities responsively to the selection of the operator.

A still further object of the invention is to provide improved saw-guide construction which permits the ready insertion of the saw-frame supports, which also are constructed novelly for the retention of the saw frame, the said sawguides being provided'with means for preventing accidental displacement of the saw-frame supports therefrom.

vide improved locking instrumentalities for securing the radius bar in anydesired angular position relative to the base support.

Further objects and advantages of the present improved construction will appear hereinafter, the-novel features and combinations being set forth in the appended claims; and the invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the claims.

The invention will be understood from a consideration of the following detailed description, taken in conjunction with the accompanying drawings which show details of the improved construction in a typical embodiment thereof, it being obvious that mechanical expedients other than those disclosed may be adopted, so that the drawings, therefore, are not to be taken as being restrictive in character.

In the accompanying drawings, Fig. 1 is, a front elevation of the improved miter-box, the View including the clamping instrumentalities for holding the stock in position for sawing operations, the stock being either metal or wood. The view indicates also certain details of the mounting of the clamping instrumentalities enabling their adjustment along the base of the miter-box for accommodation to any length of stock being sawed.

Fig. 2 15a rear elevation of the miter box of Fig. 1.

Fig. 3 is a plan view of one-half of the miterbox, including the adjustable carriage for the saw and one of the quick-acting clamps for holding the stock in position.

Fig. 4 is a sectional elevation of the miterbox taken on the line 4-4 of Figs. 1, 2 and 3 looking in the direction of the arrows and show ing certain details of one of the quick-acting clamps and its point of anchorage to the miterbox.

Fig. 5 is a sectional plan view through the swivel joint of one of the quick-acting clamps, the view being taken on the line 5-5 of Fig. 4, looking in the direction of the arrows, and showing details of one form of mechanism which may be employed for adapting the clamping screws for either quick or fine adjustment relative to the stock being sawed.

Fig. 6 is a vertical section through the releasable self-actuating locking means for the mounting brackets for the clamping screws, the view being taken generally on either of the lines 6-5 of Figs. 1 and 2.

Fig. 7 is a detail view, partly in section, of the joint on the end of the clamp screw and the cup holding the clamp pad that contacts the surface of the stock to be out.

Fig. 8 is a view partly in section and partly in elevation of certain of the details of construction, the view being taken on the line 8-3 of Fig. 3 and showing a side elevation of the front part of the adjustable carriage for the saw and a vertical section through the rear part of the said carriage showing certain details of the locking mechanism for the said carriage.

Fig. 9 is a view similar to Fig. 8, but showing a side elevation of the rear part of the carriage for the saw and a vertical section through the front part of the carriage, the view being taken on the center line of the carriage, indicated at 99 on Fig. 3 looking in the direction of the arrows.

Fig. 10 is a front elevation of the adjustable saw carriage, the view being taken on the plane of the line |5|0 of either Fig. 8 or Fig. 9, looking in the direction of the arrows.

Fig. 11 is a vertical section through the saw carriage, taken on the line of either Fig. 8 or Fig. 9, looking in the direction of the arrows.

Fig. 12 is a vertical section through the saw carriage, taken on the line |2|2 of either Fig. 8 or Fig. 9, looking in the direction of the arrows.

Fig. 13 is a vertical section through the saw carriage, taken on the line |3-i3 of either Fig. 8 or Fig. 9, looking in the direction of the arrows.

Fig. 14 is a vertical section through the saw carriage, taken on the line I i-I lof either Fig. 8 or Fig. 9, looking in the direction of the arrows.

Fig. 15 is a plan View of the locking stud lever for the radius bar of the saw carriage, showing the hole used to attach the lever to the locking stud and the slot at the opposite end for the locking rod.

Fig. 16 is a view partly in section and partly in elevation of a locking pin employed in the support for the saw frame, showing the construction of the locking pin.

Fig. 1'7 is an end view of the locking pin of Fig. 16.

Fig. 18 is a front eelvation of one of the supports for the saw frame and a stop for the frame.

Fig. 19 is aside elevation of the parts shown in Fig. 18.

Fig. 20 is a top plan view of the parts illustrated in Figs. 18 and 19.

Before proceeding with a detailed description of the invention, it may be mentioned that the improved miter box assembly of the present invention comprises, generally, a base for receiving the work or stock to be sawed, a pair of adjustably mounted brackets each carrying a quick action clamp for engaging the said stock, and an adjustable carriage to hold, guide and control the position of the saw, the said carriage including improved mechanism for positively locking the carriage in adjusted position, and which prevents accidental release of the carriage from its adjusted position.

Referring more particularly to the drawings, it will be seen that the construction includes an angle box, indicated generally by A, which is used to support the work to be cut, the saw carriage assembly being indicated generally by B, the quick action clamps for holding in the angle box B the work to be cut, being indicated generally by C, while D designates generally the lock pin assemblies for the supports for the saw frame.

The angle box assembly A comprises a frame 25, which is a substantially rectangular frame braced by rectangular reinforcing braces 2'! which are welded to the frame 25, the frame being braced also by diagonal braces 29 which are also welded to the frame. Secured to the frame 25 is a curved locking bar 3| which is generally semicircular in shape, and which is provided with attachment flanges 32 by which the locking bar is attached to the frame 25 by means of suitable bolts such as indicated at 3:1.

The frame is supported by leg units 33, which are formed in any suitable manner, conveniently from band stock which is bent to product the front and rear legs, each of the leg units extending transversely across the frame 25 on the underside thereof and which are welded to the frame.

The frame 25 carries a pair of table plates 35. 35, these plates having their adjacent edges at a sufiicient angle to each other so as to enable the saw carriage to operate between the plates and be adjusted to an angular position of at least 45 on each side of the center line. The table plates 35, 35 rest upon spacers 37, each of which spacers extends continuously around and beneath the respective plates 35, the latter being held in place on the spacers 37 and frame 25 by means of clamping hooks 39 which are anchored in the plate 35 and extend around the frame members 27, 29 and 3|.

An upstanding corrugated back plate 4| is bolted to the frame 25 by means of the bolts 34 previously described, and additional bolts 36 which pass through the corrugated plate and into the frame 25, which is provided with tapped holes for this purpose.

Adjacent to each end of the miter box assembly is a clamping assembly, designated generally by C, each of which is of identical construction, so that only one of these assemblies needs to be described in detail. Each clamping assembly C comprises an arm 43, which may be a drop forging, which is bent to form a pivot section 38 which is hinged on a pivot pin extending longitudinally of the miter box behind the corrugated plate 4|, the pin 55 being mounted in supports 4! which are secured to the corrugated plate A! by means of screws 49. The arm 33 is turnable free- 1y about the pin 45 and is slidable along the pin so as to be adjustable for any length of stock to be cut.

The arm 43 includes also a bend All at which is mounted a clamping screw 6|, which will be described in detail hereinafter. The bend in the arm 33 produces a bow in the arm which provides effective resistance to clamping stresses communicated to the arm 43 through the screw 6|, as well as providing a proper shape to the arm 43 for enabling the arm to engage the plate 35 when the arm is in secured position. This engagement is effected in the region of the free end 32 of the arm 63, which end is shaped and recessed to form a housing 48 (Fig. 6) in which is inserted a lock pin 5| which is retractably mounted in the housing 48 and which is held normally in expanded or locking position by means of a spring 53, which encloses a shank 42 of the pin 5| and which is compressed between the shoulder of the pin and the internal shoulder 46 of the housing 48. A handle or knob is threaded on the end of the shank 42' of the pin 5|, this handle knob retaining the pn 5| in its housing and also providing means whereby the pin may be retracted against the pressure of the compressed spring 53 so as to withdraw the pin 5| from its engagement with the frame 25, thus releasing the arm 43 for enabling the latter to be swung about the pivot pin 45, or moved along the pin for adjustment of the position of the arm 43.

The work to be cut is inserted in the miter box on the base plates 35, 35 by releasing and raising the arms 49 in the manner described above, and when the work is in proper position for cutting operation, the arm is dropped back into position, whereupon the lock pin 5| first strikes against the frame 25 so as to compress the spring 53 until the pin 5| is enabled to clear the frame 25. When this occurs, the spring 53 expands the lock pin 5| back into locking position, whereby the arms 43 become again rigidly secured in locking position It has been said that a clamp screw 6| is mounted at the bend 40 of each of the arms 43. For this purpose, a holder II, which will be described in detail hereinafter, is mounted in the arm 43, the screw 6| passing through this holder. The clamp screw BI is operated by turning its handle knob 59, which forces a workcontact pad 63, mounted on the lower end of the screw 6|, against the work to be cut, by transferring pressure exerted on the screw through a ball connector 65 (Fig. 7) on the end of a cup 61 and a socket 69 in the lower end of the clamp screw 6|. This ball joint connection for the pad 63 enables a firm clamping action to be had on any piece of work regardless of the shape thereof, since the engagement of the pad with the work is conformable freely to the shape thereof responsively to pressure exerted by the screw 5|.

The screw 6| is adapted to be quickly adjusted relative to the work, by in and out movement as designated by the arrow 62 in Fig. 4. In order to obtain this quick motion, a special mounting mechanism is provided which includes the holder H, which has been mentioned previously above.

In order to accommodate this holder, the bend 49 of the arm 43 is provided with a bifurcated enlargement 12 (Fig. 5) which is apertured to receive a sleeve H which is inserted in openings 95 provided in lugs 14 formed one on each section of the enlarged portion 12 of the arm 43. This sleeve H is apertured to permit the clamping screw 6| to pass freely crosswise through it and is closed at one end and forms a housing for receiving a spring 19 which is compressed between the end of the sleeve 11 and the holder "H, as will be apparent from Fig. 5. The holder l I therefore constitutes a spring pressed plunger or piston which has a hole 15 therethrough for receiving the clamping screw 6|.

This hole 15 is of a generally elliptical shape, as will be seen from Fig. 5, and it is provided with internal threads '13 which engage the clamping screw GI, the threads 13 being a half section of a full thread, the other half of the hole 75 being unthreaded, the configuration of the hole providing a clearance between the smooth or unthreaded portion of the hole and the clamping screw 5|, so that when pressure is applied to the end of the plunger H of sufficient magnitude to overcome the pressure of the spring 19, the plunger H is moved inwardly so as to clear the engagement between the threads 13 of the hole 15 and the clamping screw 6|, thus releasing the latter for free sliding movement through the hole to give a quick adjustment of the clamping screw relative to a piece of work to be cut. The movement of the plunger H is indicated clearly by the arrow 89 in Fig. 5.

When the parts are in the position indicated in Fig. 5, the clamp screw 6| is not free for a quick adjustment thereof relative to the work, but it is held by the thread 13 and can be advanced or retracted relatively to the work only I by a turning movement of the screw, which provides for a fine adjustment of the clamping screw; while, when the screw 6| is released by pressure applied to the plunger 1| so as to overcome the force of the spring 19, the threads 13 are moved out of engagement with the threads on the clamping screw, so that the latter is released for quick movement incident to the disengagement of the threads as aforesaid.

A safety catch for plunger may be provided, such as pin 8| set in plunger II and slidable therewith in slot 83 which is sufficiently long to allow sufiicient movement to the plunger to engage and release pin 6|. An opening 81 is provided in the arm 43 for enabling angularadjustment of the clamp screw 6| about the center of the sleeve 11.

With this arrangement of the quick acting clamp, work parts in the form of irregular cross sections, such as, for instance, metal or wood molding, may be quickly clamped in position in the miter box.

Reference may now be made to the supporting assembly for the saw.

This assembly is indicated generally by the character B, and inc-ludes'a front support 89 and a rear support 9| which are adapted to receive the saw frame, indicated generally at 92. These supports 89 and 9| are carried by the saw frame which passes through slots 93 and 95 provided for this purpose in the supports 89 and 9|, the saw frame 92 sliding back and forth in these slots.

The slots 93 and 95 are provided in an enlarged head portion 96 of the supports 89, 9|, the remainder of these supports being of a more restricted diameter and being in the form of an elongated rod adapted to be inserted in the tubular holders 3, H5, which will be mentioned in greater detail hereinafter.

The saw frame 92 is held in the slots 93 and 95 by spacers 91 and 99 which are inserted in the upper part of the slots, and which become flush with the periphery of the supports 89, 9|, when properly inserted. These spacers 91 and 99 are held in the supports 89 and 9| by means of a screw I91, which secures the spacers in position and positively retains the saw frame in the slots 93 and 95 so that there is no possibility of accidental displacement of the saw frame from these slots.

The front and rear supports 89 and 9| are each provided with a stop |9| for controlling the low position of the saw blade, the stop |9| engaging the upper end of the tubular holders H3 and H5, respectively, when the saw frame and supports are mounted in operative position. The stops |9| are secured in their position of desired adjustment by means of a screw 95.

The sides of the slotted ends of the front and rear supports 89 and 9| are toothed at I93, shown in Figs. 18, 19 and 20, these teeth |93 matching the corresponding teeth formed on the end of the stop ml. This arrangement prevents the slipping of stop l9! when the screw I95 is tightened. It will be seen clearly from Fig. 19 that the stop |9| is provided with a longitudinal slot ing.

I92 which receives the screw I95, whereby when the screw I95 is released, the stop I9! is released so that it may be adjusted as desired relatively to the support.

A vertical slot I99 (see, for example, Figs. 10 and 11) is provided near the lower end of the front and rear supports 99 and 9I for the insertion of a saw blade I I9, when the blade is clamped into the saw frame. The upper end of the slot I09 is made narrow, as indicated at III (see Figs. 8, 9 and 10, for example) to form a guide for the saw blade I ID, the back of the saw blade being received in the restricted portion III of the slot, and is prevented thereby from buckling during operation.

The front support 39 is held in position by a holder H3, and the rear support 9! is received in holder II5, these holders being tubular for the reception of the supports. The holder H3 is supported on a bar I ll which forms a. part of the saw carriage assembly,-and holder H5 is supported by a bar H9 which also forms a portion of the saw carriage assembly. The bar II! is provided with a groove I2I on the under side thereof, (see Figs. 11 and 13) and bar II9 is provided with a shoulder I23 which is adapted to fit into the groove I2I, the bars H7 and H9 being held together in assembled relation by means of a screw I25 which passes through these bars. This construction may be seen in Fig. 11, for example. The holders II3 and H5 are provided with a clearance slot I2! for allowing the saw to be dropped to its low position.

For facilitating the handling of the saw when placing work in the miter box, or when changing saw blades, locking pins D are provided near the top of the holders H3 and i i5, so that when the saw frame is lifted, the supports 89, 9I lock with the pins to hold the saw in raised position.

The details of the construction of these looking pins are shown in Figs. 16 and 17. The pin proper, indicated at I29, is received in a housing I3I, the pin I29 having a shank portion I39 which extends through an opening provided therefor in the end of the housing, and which is threaded, as indicated at I32, for receiving a handle member I35, which is shown as being a knob threadedly attached to the pin shank I39.

The shank I39 defines an annular shoulder I34 with the pin I29, and the housing I3I is provided with an internal annular shoulder I35, there being a coil spring I33 compressed between the shoulders I34 and I36, thereby urging the pin I 29 in extended position, retraction of the pin for insertion of the saw frame supports in the tubular holders being effected by a pull on the handle I35 sufiicient to overcome the pressure of the spring. The handle I35 also holds the pin in the housing I3I.

The locking pin I29 is provided with a fiat surface I37 which fits in a corresponding hole I38 formed in the end of the housing I3I, thereby preventing turning of the locking pin in the hous- Additionally, the end of the locking pin I29 is provided with a bevelled shoulder I49, and a flat shoulder I40, which shoulders enable the locking pin to fit in an annular groove I42 (see Fig. 9) on the lower end of the frame supports 89, 9|. Threads I39 are provided on the end of the locking pin housing I3I, as is shown clearly in Fig. 16, for securing the pins in the tubular holders II3, II5.

When the saw is operating on the work, or is resting in its low position, the locking pins I29 ride against the surface of the respective supports 89, 9I, because of the pressure of the spring I 33 against the pin I29. It is obvious, therefore, that when the saw is raised to its high position the locking pins I29 will be forced automatically into the grooves I42 of the supports, thus causing the saw to be held in its high position while at the same time looking the saw against accidental removal from the holders H3, H5. When the saw is to be lowered or removed from the tubular holders, the handle knobs I35 are pulled outwardly until disengagement is effected between the locking pins I29 and the grooves I42, thereby releasing the supports 89, 9I.

Considering now the assembly making up the adjustable saw carriage, it will be seen that this assembly includes the tubular holders H3, H5, and the bars II? and H9 which have been referred to previously, this assembly being swivelly anchored to the frame 25 by means of a swivel stud I44, (see Figs. 3, 8 and 9) which stud is received in a suitable hole extending through reinforcing bars I4I and I43 (see especially Fig. 3) which bars are welded to the frame 25. The stud I44 is fastened in the bar II9 by means of threads I46 (Fig. 8) on the end of the stud I44, which threads engage with threads in a tapped hole- I48, a set screw I (Fig. 9) being provided for locking the stud I44 in the bar II9.

Additional support for the saw carriage assembly is afforded by the provision of a clamp bar I49 which rests on the reinforcing bar I43 of the frame 25, and the arcuate locking bar 3|. This clamp bar I49 is fastened to the bar II9 by means of a stud I5I which passes through a slot I52 in the bar IIl (see Figs. 8 and 9), the stud I5I being secured in place by a screw I53 which enters the stud through the lower end thereof. Additional connection between the clamp bar I49 and the bar H9 is made by means of a stud I55 which is held by means of a screw passing through the bar H9 and into the stud as will be apparent from Figs. 8 and 9. A clearance groove I59 is provided in the clamp bar I49 for the teeth on the saw blade III).

In addition to its supporting function, the clamp bar I49 also functions as a support for the parts of the work being cut, on either side of the saw blade, preventing the said parts from binding the blade during sawing.

The mechanism for locking the saw carriage assembly is shown especially in Figs. 3, 8 and 9, this mechanism enabling the said assembly to be locked in any radial position within a 45 angle on either side of the center line of the miter box.

This locking mechanism for the saw carriage assembly includes a locking stud I6! which has a threaded end I62 entering the clamp bar I 49, the stud I6I being swivelled in the bar II9 as will be seen clearly in Figs. 8, 9 and 14. Turning movement of the stud I6I is effected by means of a lever I63 which is secured to the stud I6I by means of a flat side shoulder I65 (see Fig. 14) on the stud I6I, corresponding to a suitable hole I67 in one end of the lever I63 (see Fig. 15). A look nut I69 holds the lever I63 against shoulder I64 of the stud I6I. A washer I'II is provided on the stud I6I between the bar H9 and the lever I63 for avoiding frictional wear between these parts.

The lever I63 is operated by actuation of a rod I'I3 (Figs. 3, 8 and 14), which has one end, I14, formed so that it enters slot I15 in the lever I63. Washers I'I'I are provided on rod I 13 on either side of the lever I63, the end, I'I4, of the rod being headed over at I19 to hold the washers in place and to prevent disengagement of the rod from the lever. The rod I13 is supported in position by supports I8I, I83, which are, conveniently, screw-eyes positioned in tapped holes in bar H9. The operation of this locking mechanis will be referred to hereinafter.

The carriage assembly B for the saw is adjustable to enable the saw to cut at angles up to 45 on either side of the center line, as has been indicated above. For this purpose,'the arcuate locking bar 3| is provided with slots or notches I (Figs. 8, 9 and 12), which slots are engaged by a locking pin I81 which slides through a hole I88 in the bar H9. The pin I81 is held in the locked position by the pressure of a spring I99 against a lever I9I (see Fig. 11). This lever I9I has its end slotted so that it straddles the pin I81 (Figs. 11 and 12), and rests in a groove I93 in the pin I81. The pin I81 is withdrawn from slot I85 by upward pressure exerted on the front end of a second lever I which engages. the lever I9I on the under side of the latter, and which is provided with a slot 209. A stud 295 is riveted in the lever I9I and passes into the slot 209 to form a sliding support for the lever I95.

The bar II9 also holds a stud I91, which stud passes through a hole I99 in the lever I9I and through the slot 299 in the lever I95, this stud I91 carrying fulcrum pins 293, 294 for levers I9I and I95. The mounting of the levers I9I and I95 is such that a slight relative longitudinal movement therebetween is produced upon an exertion of sufiicient pressure on the end of lever I95 to move this lever against the pressure of spring I89 so as to compress this spring and at the same time causing lever III! to pull downwardly on the pin I81 because of the engagement of the lever I 9| in the groove I93 of the pin I81, thereby disengaging the latter from its locking position in slot I85, so that the saw carriage mechanism may be adjusted to the desired angular position.

The design of the lever mechanism for actuating the locking pin I81'is such that there is no tendency of the locking pin I81 to bind in the hole I88, but the movement is always smooth and positive. This is due to the mounting of the levers I9I and I95 to permit the relatively slight movement therebetween, and also because of the elimination of fixed pivot points which would cause the locking pin I81 to travel in an arcuate course during its movement.

Such fixed pivot points are replaced by the fulcrum pins 203, 294 over which slide the levers I9I, I95. The longitudinal sliding action between the levers I9I, I95 is only slight, but because of the clearance in the hole I99 around the stud I91, and the clearance of hole 2II around pin 291, to be described hereinafter, together also with the fact that the slot 299 in the lever I95 clears the shoulder ZI9 on the stud 205, and also because of the fact that the end of the lever I9I slides in the slot I93 in the pin I81, the movement of the pin I81 becomes a straight line movement instead of following an arcuate path.

Any binding from a side action that might be caused by pin I81 in the hole I88 in the bar H9 is eliminated by the side support provided by lever I95, and lever I9I, and the clearance of hole I99 around the pin I91, together with the.

fact that levers I91 and I95 are free to slide sideways on fulcrum pins 293, 294. It will be seen, accordingly, that levers I9I and I95 have a floating motion between them inv both longitudinal'and lateral directions so as to maintain the pin I81 free from any binding action in its movement.

In order to guide the vertical movement of the lever I95,a pin 291 is held in the bar In and '5" serves as a .guide for the lever I95, as well as limiting the longitudinal movement thereof, the lever I95 being provided with a hole ZII for receiving the pin 201. The slot 299 in the lever I95 clears the pin I81, stud I91, and stud 295, and 1'0 terminates rearwardly of the clearance hole ill I.

From the above, it will be seen that when the lever I95 is pressed up to release the pin I81 for freeing the saw carriage assembly, the latter 7 swivels around the stud I44 into the desired 1",, angular adjustment. When it is properly adjusted, the saw carriage assembly may be locked against accidental displacement by actuating the rod I13, by means of its handle end I19, this actuating the lever I63 to turn the stud IN, 20 which draws the clamp bar M9 and the bar H9 towards each other by action of the thread I92 on the end of the stud I6! sufficiently to clamp the bars together against the top and bottom surfaces of the locking bar 3|. Release thereof is effected by opposite actuation of the rod I13 and lever I99.

Notches I85 may be positioned at angles which are frequently used, so that the saw assembly may be quickly adjusted to such angles with the help of the locking pin I81. Of course, the saw assembly may be locked at any other angle where his; pin I81 does not engage one of the notches The distance between the saw supports 89 and 9| may be adjusted to change the length of move-' ment of the saw or to provide for blades of different lengths. From an inspection of Fig. 9 it will be seen that by loosening the screw I25, the bar H1 carrying the holder H3 may be drawn outwardly until the rear end of the slot I52 strikes the screw I25. During this movement the pin 291 will carry the lever I95 outwardly, as the slot 209 slides over the shoulder ZIIl of the stud 295, and the lever I95 slides over the pivot I299. When the desired position for the holder H9 is reached the screw I25 is tightened, whereupon the locking mechanism will function as before.

It is believed that the operation of the various parts of the present improved construction will be apparent from the foregoing description, and that no further reference to the operation of the parts needs to be given.

From the foregoing detailed description, it will be understood that the invention is not limited, necessarily, to the specific details of the construc- 55 tion as are herein specifically illustrated and described, as it will be apparent that such details are subject to various modifications which will become apparent readily to one skilled in the art, without departing from the spirit of the inven- 60 tion; and it will be understood, therefore, that it is intended and desired to include within the scope of the invention such modification and changes as may be necessary to adapt it to varying conditions and uses. It is also to be under-- 65 stood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall there- 70 between.

What is claimed is: I

1. In a miter box, means for clamping material to be sawed comprising in combination, a curved arm; means for securing each end of said arm to 76 said miter box; a sleeve journaled in said am and provided with a pair of opposite apertures; a clamp screw slidably mounted in said apertures; a piston reciprocable in said sleeve, said piston being provided with an elliptical aperture adapted to coincide with the apertures in said sleeve, said aperture being provided at its narrow end with half threads adapted to fit the threads on said clamp screw, said clamp screw being slidable axially through the wide end of said aperture; and means for reciprocating said piston to change the position of said clamp screw in said aperture and so to permit slow or fast adjustment thereof.

2, In a miter box, means for clamping material to be sawed comprising in combination, a curved arm; means for securing each end of said arm to said miter box; a sleeve journaled in said arm and provided with a pair of opposite apertures; a clamp screw slidably mounted in said apertures; a piston reciprooable in said sleeve, said piston being provided with an elliptical aperture adapted to coincide with the apertures in said sleeve, said aperture being provided at its narrow end with half threads adapted to fit the threads on said clamp screw, said clam screw being slidable axially through the wide end of said aperture; and spring and stop means for controlling reciprocation of said piston to change the position of said clamp screw in said aperture and so to permit slow or fast adjustment thereof.

3. In a miter box, means for clamping material to be sawed comprising in combination, a curved arm; means mounted on said miter box providing a pivot for one end of said arm, said arm being slidable along said pivot means; substantially instantaneously releasable means for securing the other end of said arm to said miter box; a sleeve journaled in said arm and provided with a pair of opposite apertures; a clamp screw slidably mounted in said apertures; a piston reciprocable in said sleeve, said piston being provided with an elliptical aperture adapted to coincide with the apertures in said sleeve, said aperture being provided at its narrow end with half threads adapted to fit the threads on said clamp screw, said clamp screw being slidable axially through the wide end of said aperture; and means for reciprocating said piston to change the position of said clamp screw in said aperture and so to permit slow or fast adjustment thereof.

4. In a miter box, means for clamping material to be sawed comprising in combination, a curved arm; a pin mounted on said miter box providing a pivot for one end of said arm, said arm being slidable along said pin; spring controlled releasable means for locking the other end of said arm to said miter box; a sleeve journaled in said arm and provided with a pair of opposite apertures; a clamp screw slidably mounted in said apertures; a piston reciprocable in said sleeve, said piston being provided with an elliptical aperture adapt- WILLIAIW J. PARSONS.

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