US1684090A - Miter jack and coping cutter - Google Patents

Description

Sept. 11', 1928. I 1,684,090 I w. H. GREENFIELD MITER JACK AND COPING CUTTER Filed May 4, 1925 I V William H Greenfield a Ho: new

Patented Sept. 11, 1928.

Uili'ifEl) STATES WILLIAM H. GREENFI ELD, OF SEATTLE, XVASHINGTON.

MITER JACK AND COPING CUTTER.

Application filed May 4, 1926. Serial No. 106,777.

My invention relates to a miter ack haying certain advantages, to be hereinafter described 11 detail, and to a combined miter jack and coping cutter.

Miter -jacks heretofore employed have been open to several serious objections, one of the most important of which is that they were so arranged as to endanger the fingers of an operator. The operator must hold the piece being mitered close to the knives,and by reasonof the arrangement of the ordinary acks, and the necessary position of the operator in operating them with his entire hand projecting into the narrow angular space between the work guide and the knife, he would occasionally have his fingers caught by the knife while thus holding the work. Furthermore, such miter acks were only approximately accurate, and it has been assumed that the knife-carrying head could not be held exactly rigid, and it has consequently been rather loosely held, and therefore subject to variations with respect to the cutting edge of the working table. This lack of rigidity, while not of extreme importance in simple miter jacks, rendered it impossible to employ such a miter jack for the purpose of a coping cutter.

Among my objects, therefore, are to improve the miter jack heretofore produced by so arranging the parts that the workers hands, in the position they will naturally assume in holding the work, will remain clear of the knives, and yet will hold the work as closely as is ever necessary to the cutting edge; to provide a miter jack in which the miter head is rigidly held with respect to the work table, and therefore to enable a coping cutter to be combined with the miter jack, thus reducing the number of machines necessary and eliminating the space required by a second machine.

"Other objects include the general simplification andimprovement of the machine; and cheapening its cost of manufacture and assembly, while improving and simplifying its general operation, and the visibility of the operator, standing in the position he would assumein operating the machine.

My invention comprises the'novel parts and the novel combinations and arrange ments thereof as shown in the accompanying drawings, described in the following spech ficatioii and particularly defined by the claims terminating the tame.

In the accompanying drawings I have shown my invention embodied ina machine which represents the present preferred construction. c

Figure 1 is a perspective view of the machine complete, viewing it from the operating side.

Figure 2 is a plan view of the machine.

Figure 3 is avertical section along the line of the operating pedal. 1'

Figure 4 is a front elevation of the upper portion of the machine. i

Figure 5 is a section on line 55 of Figure 2. I I V V In all. such machines a miter head, as 1, is movable vertically relative to a horizontal work table 2, this work table generally hayeXtensions 25 at each side of the main casting 29, and having an angular notch 20' out to allow the passage of the head i and the knife carried thereby. Thus the cooperation of the inclined lower edges of the knives 10 with the edges of the notch shears off the molding or like'material which is to be mitered, and which is indicated in dotted lines at M in Figure 3.

As I have shown in the drawings, the main casting 29, whereon is formed the work table 2, is supported from the floor by a suitable stand, that shown herein comprisng legs 3, receivable in sockets 23 provided in the under side of the cii llingEZQ, and being secured to a lower table 31 to prevent their ends from spreading. The work table, as is customary, is provided with a backing flange 22 which may be supplemented by a wooden backing strip 24, and the lateral extensions of the work table may be formed either as an integral part of the main casting, or as shown herein, and for convenience of construction, they may be attached to the sides .of the casting 29,. The details of constructi on of the stand or support, and of the Work table, may be varied, it beingunderstood that it is one of my objects'to simplify the construction of the ack.

In order to insure rigidity of the headl relative to the table 2, the head, according. to my invention, is supported solely upon a vertical rod 4;, which rod is mounted for vertical reciprocation in two guides 32 and 33 which are formed respectively in the main casting 29 and in the lower table 31. The chief guide is the guide in the main h -sis he i106 .lfih 1 7 rod 4. and head 1.

rigidly held with relation to the work table, and constrained by the aligned guides 32 and 33 to move without variation laterally from its path, the head 1, which is rigidly secured thereto, will likewise move in a definitely fixed and invariable path. As a convenient means for securing the head in place, the upper end ll of the rod t may be reduced, and this reduced end is received in a bore 11 of the head 1, the head being finally clamped in place by a nut 14: thrcading upon the upper end of the rod l. The knives 10 can be so arranged that their lower and forward corners do not pass from engagement from the sides of .the notch 20, and thus the head is insured of passing into the notch into exact relationship thereto. The collar 42, fixed upon the rod 4, limits the upward movement thereof under the influence of springs 43 extending between the main. casting and a yoke l i secured upon the rod a below the table, and adjustable axially of the rod, as by means of the set screw 45, to vary the tension of the springs 43.

To prevent twisting of the rod 4 about its axis, and consequent dislocation of the head.

1 relative to the notch 20, guides, such as the apertured ears 4-6 may be provided, these extending radially from the collar 42, and being slidable over fixed guide rods 26, which in turn are received. in sockets 27 in the under side of the main casting. By this construction, the rod 4, which carries the head, is guided not only in the guide 32 in the main casting, but also by the guide rods 26, likewise secured in the same casting, and in this casting is formed the notch 20, which co-operates with the knives 10 on the miter head; thus the two parts which by their relative movement co-operate to effect the cutting are rigidly constrained to move in a given line, and may not deviate from this line. There is'no opportunity, due to the position of bearings in separated members,

ordue to t IGPOS SiblG wear of two lateral gu de members, for the head to wabble, for the main guide for the head is at all times the guide'32, and the guides 33 am 26 serve merely to assist this guide in preventing tilting or twisting of the rod and thus to prevent undue wear on the main guide 32.

The reciprocation of the rod 4; and the head which is carried thereby may be effected in any suitable manner, and as shown herein, 1 have provided a pedal lever 5, fulcrumed at 50 upon an extension 51 below the lower table 31, the pedal lever being connected between its ends, and by means of a link 5%, to the lower end of the rod 4:. This lever is provided with a tread 53, which is engaged by the foot of the operator to depress thepedal lever, and consequently the The position of the collar 441- relative to the lower table 31 serves of considerablevertical extent, such an arrangement would not be feasible for the reason that the operator would be unable to see the work except by bending over the head and peering directly down between the head and backing flange. By reason of the elimination of the side guides for the head and the support of the head from below upon a single centrally located rod, it is possible to cut down the vertical height of; the head at its sides, as is best illustrated in Fig ures 1 and 3. This in itself affords greater visibility to the operator, and he need not,

bend over the head to View the work.

Further, by reason of the arrangement of the pedal lever relative to the work table and its backing flange, it now becomes most convenient to hold the work achacent the notch 20 with the thumbs instead of with the fingers. Thus the thumbs, placed in their natural position, and as indicated in Figure 2,.press the work backward and away from the operator, and against the flange 32 or the strip 24L. With previous machines it has been necessary to draw the work toward the operator, using the first fingers of the hand, and with the fingers in this position they naturally assumed a position in line with the movement of the knives l0, and thus great danger resulted to the operators fingers, if he became careless in the least. Vith my arrangement, it is natural for the thumbs to press the material backwards, the fingers extending over the backing strip 24-, and the natural position of the thumbs being at an angle to the backing strip corresponding'closely to the angle of the knives 10.

.This advantage is a direct result of the elimmatron of the side guides for the head and the support ng ofthe head from below on a single centrally located rod;

It is desirable to provide coping cutters for use with a miter jack, but heretofore the construction of miterjacks employing a head guided at opposite sides has precluded the employment of such coping cutters by reason of the fact that the coping cutter must be rigidly held-relative to the work,-and the loose support of the miter jack made this impracticable. VVitha head mounted rigidly, as is the casein my construction, it be comes possible to support a supplemental coping head 6, as by means of the bolts 60, and to support coping knives 61 in such a head in operative relation to coping tables 7. The knives 61 maybe secured in any manner desired, and as shown herein, a clamping plate 62, held by a bolt 63, secures the knives in position, and these knives are backed by an adjusting screw 64.

To enable angular adjustment of the coping tables 7, they have been illustrated as pivotally mounted at 72 upon the main casting 29. The angle of these tables may be adjusted by means of a segmental slotted guide 71 cooperating with a clamping bolt 70, received in the main casting. As is the case with the miter table, these coping tables 7 are duplicated, one extending at each side of the path of the knives to enable right or left hand cutting. Such coping tables are ordinarily employed with a mold ing strip 74%, the reverse of the coping strip C which is to be cut.

Another advantage flowing from the rigid support of the miter head relative to the work table is the possibility of providing clearance as the knives progress, as is illustrated in Figure 5, somewhat exaggerated. The knives 10, from their edges, are inclined slightly away from the vertical with respect to the plane of the notch 20. Hence, as it cuts through a strip of molding M the cutting edge only will engage the molding, and the surface of the knives will not engage the molding to force it back. The result is a clear, accurate cut, exactly on the plane intended, and not a broken, ragged cut, or one which is inclined, as sometimes occurs where no clearance can be provided. The clearance need not be great, a few thou,-

sandths of an inch only being necessary,

owing .to the rigid support of the head 1, whereas a clearance considerably greater, as might be required were the head not rigidly held, would not be practicable.

hat I claim as my invention is:

1. In a miter jack, the combination with a supporting frame having a laterally-dis posed work table, of a vertical guide carried by said frame below the work table, a miter head vertically movable relati-veto said table, and normally thereabove, and a rod vertically reeiprocable in said guide, said rod being secured in said head to form the sole support and guide thereof.

2., In a miter ack, the combination with a supporting frame having a horizontal work table and vertically aligned guides wholly therebelow, a miter head disposed above said table and vertically reciprocable relative thereto, and a rod forming the sole supportand guide for said head, and receivable in said guides for vertical reciprocation, and

means connected with said rod for reciproeating said head.

3. In a miter jack, in combination with a supporting frame having axially aligned crtical guides and a laterally disposed work table adjacent and above said guides, a rod received in said guides for vertical reciprocation, said rod extending above and below the work table, a head rigidly supported on the upper end of said rod, and otherwise unsupported knives carried by said head above said table, and pedal-controlled means operatively connected with the lower end of said rod for reciprocating said head by means of said rod.

4t. In a miter jack, the combination with a supporting frame having vertically aligned guides and a laterally disposed work table, a head reciprocable above and co-operating with said work table, a rod vertical y reciprocable in said guides, said head being rigidly secured upon the upper end of said rod, laterally spaced vertical guides supported in said frame and extending parallel to said first guides, guide means carried by said rod and co-operating with said spaced guides to maintain said rod against rotation about its axis, and means for vertically reciprocating said rod and the head carried thereby relative to said work table.

5. A combined miter jack and coping cutter comprising in combination, a supporting frame having vertical, axially guides, a transverse miter table supported on said frame adjacent the axis offlsaid guides, tiltable coping tables likewise disposed adjacent the axis of said guides, a bead disposed above said tables, a rod supported in said guides for vertical reciprocation and forming the sole support of said head, miter knives carried by said head and co-operating with said miter table, means carried by said head for supporting coping knives in operative posit-ion relative to said coping table, and means for'reciprocating said rod and the head carried thereby rela tive tosaid tables.

6. In a miter jack, in combination with a miter table having a backing flange, and having a notch disposed .angularly relative to said flange, a miter head above said table and reciprocable relative theretoto enter said notch, and means engaging said head wholly from below, and forming the sole means for supporting and guiding for re ciprocation, said flange, said head, and said operating. means being disposed with the flange beyond the head from the operating means.

7 In a miter jack, in combination with a notched miter table having a vertical guide disposed within the notch and below the working surface of the table, a miter head above said table and movable vertically relative thereto to enter said notch, a rod reciprocable in said guides, said rod engag? ing said head from below and formingits sole support and guide, and means engageable with said rod below the table for reciprocating said rod.

8. In a miter jack, in combination with.

aligned iii a miter table, a miter head above said table and movable vertically relative thereto, said ta le having a vertical guide wholly below said head in all its positions, and said head having its upper side edges inclined clownwardly and forwardly, a rod reciprocable in said guide, said rod engaging said head from below and forming its sole support, and means for reciprocating said rod.

9. In a miter jack, in combination with a miter table having a backing flange, a miter head above said table and movable vertically relative thereto, a rod engaging said head from beneath, and forming its sole support, vertical guides in said table below all positions of the head, said rod being reciprocable in said guides, means projecting at the side of the table opposite the backing flange for reciprocating said rod, and the upper side edges of said-head being inclined downwardly and towards the operators position, to render visible the table space between the head and the backing flange.

1O.-A combined miter jack and coping cutter comprising, in combination, a supporting. frame having a laterally disposed notched miter table, a coping table supported on said frame, a head, means carried in said frame below the tables, and forming the sole support and guide of said head, whereby it is disposed, above said tables for reciprocation downward thereto, miter and coping knives adapted to be secured to said head and to co-operate with the respective tables as the head is reciprocated relative thereto, and means for reciprocating said head through said supporting means.

11. In a miter jack, in combination with a miter head, a miter table having a backing flange upstanding therefrom, and having a notch to receive the cutting face'of said miter head and disposed at an angle to the backing flange, vertical guides in said table below its working surface,and within said notch, a rod vertically reciprocable in said guides, and being secured in said head to form the sole support and guide thereof, there being no guide means engageable with said head itself, and means engageable with said rod beneath the table for reciprocating said head relative to the table, said means being operable from the side of the table opposite said flange.

12. In a miter jack, the combinaticnwith a notched worktable, a head normally above and reciprocable towards and from said table, and knives carried by said headand reciproeable therewith past the edges of the notch in said table, a frame supporting said table and having a vertical guide having its axis disposed in alignment with said notch, and located below the work table, a rodvertically reciprocable in said guide, said head being rigidly secured upon said rod, laterally spaced guides supported in said frame below the table outside of said notch, and parallel to the axis of said first guide, guide means carried by said rod below the work table and co-operating with said spaced guides to maintain said rod against rotation about its axis, and means for vertically reciprocating the working unit, consisting of the rod, head. knives, and guide means. i

13. A miter jack as in claim 3,, including co-operating guide means carried by's'aidv rod and said frame, below the work table, for preventing turning of the head about the axis of said rod. l

14. In a miter jack, in combination with a miter table. having a backing flange, and

having a notch disposed angularly relative to said flange, a miter head adapted to be reciprocated within said notch, a portion of said miter head engaging said notch in all positions of said head to prevent its rotation, and means engaging said head from below to reciprocate said head and to form the sole means of support thereof.

15. In a miter jack, in combination wit a miter table having a backing flange, and having a notch disposed angularly relative to said flange, a miter head above said table and reciprocable' relative thereto to enter said notch, and a rod supporting said head and adapted to reciprocate said head, laterally spaced vertical guides supported below said table and a guide member slidable in said guides and secured to said rod to prevent rotation of the head.

Signed at Seattle, King County, \Vashington, this 26th day of April, 1926.

WILLIAM 1-1. GREENFIELD.

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