US2940485A

US2940485A - Woodworking apparatus for cutting a miter on trim and door stops

Info

Publication number: US2940485A
Application number: US681010A
Authority: US
Inventors: Warren B Zern
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-08-29
Filing date: 1957-08-29
Publication date: 1960-06-14
Anticipated expiration: 1977-06-14

Description

June 14, 1960 w. B. ZERN WOODWORKING APPARATUS FOR CUTTING A MITER ON TRIM AND DOOR STOPS 2 Sheets-Sheet 1 Filid Aug. 29, 1957 June 14, 1960 w. s. ZERN 2,940,485

WOODWORKING APPARATUS FOR CUTTING A MITER ON TRIM AND DOOR STOPS Filed Aug. 29, 1957 2 Sheets-Sheet 2 United States Patent -WOODWORKJNG APPARATUS FOR CUTTING A 'MITER ON TRIM AND DOOR STOPS Warren B. Zern, RD. 3, near Pottstown, Pa.

Filed Aug. 29, 1957, Ser. No. 681,010

11 Claims. (Cl. 143-38) This invention relates to woodworking apparatus and has for an object the provision of improved means for cutting trim and door stops with the proper miter to form miter joints on door frames. Although not limited thereto, the invention is particularly applicable to cutting the miter or bevel on the trim strips nad door stopping for use on pre-hung doors. The present invention enables even an unskilled workman to cut the proper miter on trim strips and door stops both quickly and accurately so that when the door stops and trim strips are formed into miter joints around the door frame, they will fit perfectly and provide a good appearance.

One of the most difiicult jobs in preparing trim strips for doors or windows is to cut the various pieces to the correct length and with the proper miter, so that when the head trim and side trim are assembled around the frame, their corresponding ends will form tight closefitting miter joints. If only a slight error in dimension is made, the adjoining ends of the trim will be spaced apart and will not present a tight-fitting miter joint. This results in a poor-fitting joint and one which presents a poor appearance and is not acceptable in the building trade.

The present invention is adapted to eliminate the foregoing difiiculties and insures that the miter cuts on the dor trim and door stop will be accurate and form tightfitting miter joints when assembled. In accordance with the present invention there is provided a work table over which extend two rotary blade power saws of the radial arm type. The free ends of the arms are locked together so that the tracks along which the saws are adapted to more form an angle therebetween of precisely 90. A work holder is disposed on the table between the saw tracks and is adapted .to receive a piece of work, such as trim strips or door stop strips. The two saws are adapted to be moved separately to cut the miters on the side trim andthe side stops, or they can be moved together to concurrently cut off the ends of a head stop or the head trim. The important dimension in cutting the head trim is to maintain the dimension along the inner edge of the trim. This is the dimension that must fit at the head of the door where it engages the two side trim pieces to form the miter joints. The work holder is of novel design and is adapted to locate the head trim from the inner edge adjacent the jamb and thus eliminate errors which occur due to the non-uniform width of the trim strip.

The two most common types of trim used today are those known by the names Colonial and Ranch. These trim strips are shaped in a mill before they are delivered to the lamber yards. While the trim strips are supposed to be cut to various standard widths, it is a well known fact today that trim strips do not run true in width throughout their length and vary from strip to strip by as much as one-eighth inch or more. Such variations in width of the trim strips have caused considerable difliculty in the past for workmen when they form these strips into miter joints around the frame of a door or window. The'present invention eliminates this difficulty, and it does not matter if the trim is wider or narrower than the standard width since the dimension along the inside edge of the trim is maintained accurately during the miter-cutting operation.

It is a further object of the invention to provide close fitting miter joints on the trim by cutting feather edge niiters. This is accomplished by supporting a trim strip in a horizontal plane at a pair of spaced locations. The trim strip is pressed downwardly between the spaced locations to how the trim strip and cause the ends thereof to be raised above the horizontal plane. While the trim strip is held in this bowed position, at least one of the ends of the trim strip is cut off at an angle of 45 with respect to its length and along a plane perpendicular to the horizontal plane. This provides a feather edge miter along the upper surface of the trim strip which is the exposed surface of the trim strip when it is placed around a door frame and formed into miter joints at the head end of the door frame. In the case of a head trim strip, both of its ends are cut off at 45 angles, whereas only one end is cut at a 45 angle on the two side trim strips.

Further in accordance with the invention, there is provided a novel work holder for holding door strips during the miter-cutting operation, and each of the novel work holders employs spring-biasing means for forcing the respective stop strims and trim strips against a locating surface.

For a more detailed disclosure of the invention and for further objects and advantages thereof, reference is to be had to the following description taken in conjunction with the accompanying drawings, in which:

Fig. l is a front elevation of apparatus embodying the present invention; v

Fig. 2 is a top plan view of the apparatus shown in Fig. 1;

Fig. 3 is an exploded fractional view in perspective showing the novel workholder of Figs. 1 and 2 in raised position above the work bench;

Fig. 3A is a fractional sectional view taken along lines 3A3A in Fig. 3;

Fig. 4 is a bottom view of the work holder shown in Fig. 3;

Fig. 5 is a fractional sectional view showing the springbiasing means of the work holder taken along the lines 55 in Fig. 6;

Fig. 6 is a perspective view of the work holder for the door trim;

Fig. 7 is a perspective view of an end locater for the door stop;

Fig. 8 is a perspective view of an end locator for the trim strips; and

Fig. 9 is a fractional view of a door frame showing miter joints formed by trim strips and door stopping.

Referring to Fig. l, a work table 10 is shown supported on a floor F. The table 10 includes a plurality of vertical legs 11 which are adapted to support a horizontally disposed table top 12 on which the work, for example, door trim strip or door stop strip, is adapted to be positioned. The table 10 also includes another horizontal section 13 which is adapted to support a pair of rotary

blade power saws

14 and 15. The power saws 14 and 15 may be of any suitable type; however, they have been illustrated as radial arm saws which are well known in the woodworking trade. Briefly, each of the

saws

14 and 15 includes base 16 above which projects a vertical post 17. One end of an arm 18 is connected to the top end of the post 17, the arm including a track along which the power saw is adapted to move. Each of the

power saws

14 and 15 includes an electric motor 14a, 15a, Fig. 2, the respective shafts of which are provided with a

rotary saw blade

14b and 15b, respectively.

will rest on the raised portions 25a.

7 3 a V r 7 Each of the motors 14a and 15a is supported in its re

spective carriage

14c, 150, which is adapted to slide along the tracks in the respective arms 18. Each saw is provided withfa handle 14a and 15d, so that the sawsmay be moved individually alongJtheir respective tracks;

.. .Asvrnay be seen'in Figs. 1 and 2, the outer or free.

. ends of the arms 18 which include @thetr'acks are-locked together by a pair of brackets 20.. Thebrackets 29 are adapted -to..be secured to the ends of the arms 18 by' suitable means, for example, as by screws 21, Fig. 2. Aswill be seen in Fig. 2, the brackets 20 lock-the arms and thus the tracks for the saws, together so as to form anangle'therebetween of-precisely 90; At therear of.

the table top 12, there is provided a fence or guard 23. The fence 23 extends lengthwise of the table, and is per pendicular to a line bisecting'the angle formed between the tracks forthe two saws. In front of the fence 23 and between the

twosaws

14 and 15 is a work holder 25. The work holder 25 is adapted to support the work, illustrated in Fig. 2 as a trim strip T, lengthwise of the table top 12 and precisely perpendicular to the bisector of the right angle formed'betweenthe tracks in the arms 18 for the

saws

14 and 15.

The work holder 25 (Figs. 3 and 4) preferably .is formed from metal, such as for example, as an aluminum casting. It comprises'a bottom plate 26 in the shape of an isosceles trapezoid, having a pair of parallel sides of unequal length and a pair of angular sides which are inclined at 45 which is the angle of the miter. These sides are provided with a plurality of projections 27 spaced apart a distance somewhat greater than the width of the trim strip T placed therebetweem This relationship may be seen in Fig. 2. The workholder 25 serves to support the trim strips during the cutting of both the side trim T T and also the head trim T Fig. 9. The projections 27' are adapted to serveas locating surfaces for the trim strips. The trim strips are inserted in the work holder 25 with the inner edge of the trim strip being in engagement with the surface of member 27. This is accomplished by means of a spring-biased device illustrated in Figs. 2 and ,3 as a cam member 29 which is supported on a flexible strip spring member 30, the ends of which are held between a pair of posts 31. It'will be noted that in Fig. 3, the'work holder 25 is provided with two complete sets of locating members 27 and spring-biasing devices 29-3 0, and thus two different lengths of head trim strips may be cut with the same work holder. Thus, for example, the work holder 25 may be used for cutting the head trim for a, door frame which is 24" wide and one which is 28' wide It is to be understood that the work holder 25 may be constructed to cut head trim of any selected width. The

trim is inserted in the work holderwith the inner edge of the trim in engagement with the locating surfaces 27, and the rear edge or outer edge of the trim is engaged by the cam surface 29. The cam surface 29 is so positioned that in order to'insert the trim in place on the raised portions 25a'at the ends of the plate 26, it will be necessary to bow the spring 30. This insures that the front edge of the trim strip will be held tightly against the locating surfaces 27, as illustrated in Fig. 2. When the trim strips are in place in the work holder 25, they When the miter is being cut, the operator can press the trim strip downwardly so that it engages the plate 26 between the raised portions 25a. 7 This recessed construction of the work holder 25 permits 'the trim strip to be bowed slightly,

thus providing a feather edge onthe miter which will insure the formationof a perfect miter joint.

As maybe seen in Fig. 3, the surface 12 of the table as recessed at 35 to receive the workholdcr 25. The

depth of the recess 35 is; suchthat when the trim strips holder 25 in the recess 35 so that the

saws

14 and 15 will cut oif the ends of the trim strips at an angle of precisely 45, the bottom of the recess 35 is provided with a pair of spaced openings 36 which are adapted to receive a pair of spaced locating blocks 37 which project from the bottom surface 'of plate 26 of the work holder 25, Fig; 4 V U. 1

As may be seen in Figs. 3 and 4, the locating blocks 37 are adapted to be secured to the plate 2l6 by a double locking arrangement. The upper surface of plate 26 is provided with elongated slots 38 through which extend screws 39. The slots 38 are recessed, as shown in Fig. 3A, to receive the heads of the screws 39 so'that the latter will not interfere with the trim strips. The lower threaded ends of the screws 39 are'adapted to extend into the threaded openings in the locating blocks 37,'as shown in Fig. 4; Thus, the screws 39 maybe moved lengthwise attire slots 38. and transverselyof theplate 26 for adjustment purposes. As shown in Fig. 4, similar elongated slots 40 are provided in blocks 37 through which screws 41 are adapted to be received, in-.,threaded openings in the plate 26, as may be seen inFig; 3A.

The foregoing adjustment of the locating blocks 37 is provided for two purposes. First, it permits thework holder 25 to be adjusted with respect to the

saws

14 and 15 .so that the

saw blades

14b and 15b will cut 05 the ends of the trim strip at anglesof precisely 45 The adjustment of the loacting blocks 37 also permits the from a one-eighth inch exposed jamb set-up to a onequarter inch exposed jamb set-up, it is necessary to increase the length of the head trim T by one-quarter inch. To accomplish this, the

screws

39 and 41 are loosened in the loacting blocks 37 and the'locating blocks moved with respect to the plate '26 so that the plate 26 sets farther toward the rear-of the recess 35. in Fig. 3. The amount of adjustment'is such that the length of the head trim T to be cut in the workholder 25 will be increased by the desired amount. To change to a smaller amount of exposed jamb J around the edge of the trim strips T T T Fig. 9, the locating blocks. 37, Fig. 4, would be moved in reverse fashion withrespect to the work plate 26. 1 V

The locating blocks 37 are precisely machined so that they closely fit the openings 36 in the table 12. The openings 36. are formed in metal blocks to insurev that the work holder 25 will not move once the locating blocks 37 are inserted in the recesses or openings 36. In order to prevent woodchips from tilting the work holder 25, the bottom of the plate 26 is provided with four projections or raised portions 45 which are adapted to engage the bottom of the recess 35.. Thus the work holder 25 rests on the four projections 45 within the recess 35, rather than the entire lower surface of plate 26 engaging the bot-tom of the recess 35.

As may be seen in Fig. 2, apiecev of T is inserted in the work holder25 ready for cutting. It is to be noted that the inner edge of thetrim T has been positioned against one set ofthe locating members27and the thick outer edge of the trim is engaged by the springbiased member 29, forcing the inner edge against the locating members 27. .In cutting a piece of head trim, T

both of the

saws

14 and 15 are moved along their-respective tracks 18 and thus both ends of the strip T are provided with miter cuts which are precisely at 45 with respect to the longitudinal axis of the trim strip T.

The same set-up asdescribedahove is also adapted for cuttingzthe miter on the ends of the. side strips.

To cut a left-hand trim strip, T Fig. 9, a locating device 50, Fig. 2, is employed to position the bottom end of the trim strip at the proper distance from the blade 15b of saw 15. The table is provided with a metal plate 51 which is recessed in the surface 12 and is provided with a plurality of openings 52 which are spaced apart a predetermined distance, for example, one inch. The locating device 50, Fig. 8, is provided with a pair of pins 53 which depend from the body portion and are adapted to be received in the openings 52 in the metal strip 51 on the surface of the table. One end of the device 50 is provided with a locating member having a vertical portion 54 which is adapted to engage the flat end of the trim strip T and a horizontal portion 55 which is adapted to overlie the trim strip T in the manner illustrated in Fig. 2. For small adjustments of the vertical portion 54 of the locating member lengthwise of the table 10, there is provided a plurality of Washers 56 located between the body member and the vertical portion 54, Fig. 8. Once the locating device 50 has been properly positioned for locating the side trim T relative to the saw 15, it may be locked to the table by means of a bolt 57 which is adapted to extend through the body member into the strip 51.

With the trim strip in place, as shown in Fig. 2, the miter at the head end of the strip is cut by moving the saw along its track toward the operator. The saw 14 is not used during this operation. To cut a right-hand trim strip T for the other side of the door frame, the 10- cating device 50 is moved to the opposite end of the table 10 and inserted in the proper opening in a strip 61 which corresponds to strip 51, described above. For convenience, the table 10 may be provided with a pair of locating devices 50, one to cooperate with each of strips 51 and- 61 at the opposite ends of the table. It will be seen that when the trim strip T is inserted at the opposite end of the table, the miter will be cut by saw 14 in a similar manner to that of saw 15, previously described. Thus, it will be seen that the pair of

saws

14 and 15 are used not only to cut side trim strips T T but also the head trim strip T 7 The

saws

14 and 15 are also used to cut the door stopping S S S, which is to be mounted along the jambs I of the door frame in a manner illustrated in Fig. 9. A work holder 65, Fig. 6, is adapted to be mounted in the recess 35 in the table top 12 in a similar manner to the work holder 25. The work holder 65 comprises a bottom plate 66 having a plurality of sets of projections 67 which extend thereabove. The sets of projections form a plurality of slots or recesses corresponding in length to the Widths of various door frames, for example, from 18" to 36". The projections 67 are each provided with a locating surface 67a against which the door stop strips are adapted to be held. The surface of the door stop strips which engages the jamb is held against the locating surface 67a of the work holder by means of a spring 69 which is L-shaped and one end of which extends into the recess between the sets of projections 67 and is adapted to engage the surface 67b, as shown in Fig. 5. The springs 69 are secured to the respective projections 67 by means of screws 70.

The work holder 65 for holding the door stop members is used in a similar manner to the work holder described above. In cutting the head stop S the work is inserted in the appropriate slot formed by the set of projections 67 corresponding to the width of the door frame opening. The flat or rear surface of the head stop S which engages the jamb is the surface which must be cut accurately to length. It is for that reason that this surface is held against the locating surface 67a in the work holder 65. Thus, if the door stop material varies in thickness, it will still be cut to the proper length. The miter cuts are made at the ends of the head stop S by moving both of the

saws

14 and 15 along their respective tracks 18 in the manner described above in connection with cutting a head trim strip T To cut a side door stop member, 8;

or S,, the strip material is placed in the first one of the slots on the work holder 65 adjacent the fence 23 on the table. It will be noted that in Fig. 2, the surface 12 of the table 10 is provided with a locating device which is adapted to engage the bottom end of a side door stop strip. The locating device 80 is similar to the device 50 employed in connection with side trim strips T T except it is provided with a U-shaped member 81 which is adapted to receive the bottom end of a door stop strip. Since the door stop strips are inserted vertically in the work holder 65, they are likewise inserted vertically along their edges into the U-shaped member 81, Fig. 2. The table is provided at its right-hand end with a metal strip 83, having a series of openings 84 which are adapted to receive the pins 85 which project from the bottom of the device 80. For small adjustments in spacing, the U- shaped member 81 is separated from the body portion of device 80 by a series of washers 86 similar to the washers 56 used on device 50. A strip 88 similar to strip 83 is located at the opposite end of the table top 12, as shown in Fig. 2. When the locating device 80 is positioned in the strip 83 at the right-hand end of the table, as shown in Fig. 2, the saw 14 is used to make the miter cut at the head end of the door stop strip 8,. To cut the door stop strip S for the opposite side of the door, the device 80 is positioned in the corresponding holes of strip 88 at the opposite end of the table and saw 15 is used to make the miter cut at the head end of that door stop strip.

From the foregoing description, it will be seen that the apparatus provides an arrangement whereby the door trim T and the door stops S will be cut accurately to length and the miter cuts will be precisely at 45 with respect to the length of the strips and thus will form perfect miter joints at the upper corners of the door frame, 'Fig. 9. This apparatus not only permits the operator to be assured that his miter joints will fit perfectly but also enables him to cut the trim strips T and door stop strips S much more rapidly than in the past.

Although it has been described as a preferred embodiment of the invention, it will be understood that further modifications may be made without departing from the spirit and scope of the invention, as set forth in the appended claims.

What is claimed is: g i

1. Apparatus for cutting miters on work such as trim strips for doors or the like to form precise miter joints, comprising a table having a horizontal section on which the work is adapted to be positioned, a pair of saws, each of .said saws having a rotary blade, a pair of vertical supports for said saws, each of said saws having a horizontal overhead track to guide the movement of said blades along straight horizontal cutting paths corresponding to the positions of said tracks, said pair of supports for said saws being spaced apart at the rear of said table, said tracks being connected at their rear ends to the re- 'spective supports so that they extend radially therefrom,

the outer end of each track for the respective saws being locked to that of the other to maintain said tracks at an angle therebetween of 90, a workholder on said table for supporting work between and below said tracks and across said cutting paths of said saws, said workholder including guide structure for positioning the longitudinal axis of the work along a line perpendicular to the bisector of said 90 angle so that movement of said saws along their respective tracks will cause said saw blades to cut the ends of the work at angles of precisely 45, and a recess in the upper surface of said table, said recess having a configuration corresponding to the configuration of said workholder for receiving said workholder therein.

2. Apparatus according to claim 1 wherein said recess and said work holder are shaped in the form of a trapezoid, the angular sides of which are respectively parallel to said tracks for said saws.

f4; Apparatusaecording to claim 1 i /herein said work holderfincludesaibottom plate'adapted to be received -in said;rece ss,;and structureonsaid plate adapted to cooperatelwithf structure in said recess to locate said workholder and hold it in a predetermined position relative to the-bisector of said 90? angle, said structure on said plate being-adjustable to move thelongitudinal axis of the work perpendicular to saidbisector of said 90 angle to warywithin narrow predetermined limits the length to which the work is cut'by said pair of saws. V

5;, Apparatus according to claim 1 wherein said workholdel'finsludes a plate having structure adjacent the paths oi the sawsifor supporting the work at a predetermined elevation thecentral area of said plate being lower than said work-supporting structure, whereby the work may be pressed against said central area so as to bow the work andenable'said saws to cut a feather edge at the ds oftthe kt h f 6. Apparatus according to claim 1 wherein said workholder includes a bottom plateadapted to be received in said-recess, an opening in the bottom of said recess, said opening having a metal lining, said bottom plate having a locating block'projecting from the bottom surface thereof and having a configuration corresponding to 'the configuration of said metal-lined opening in said recess, said locating block being adapted to be inserted in said metal lined opening for precisely positioning said workholder relative to said tracks of said saws.

7. Apparatus according to claim 6 wherein said bottom plate of said workholder is provided with at least three raised portions which are adapted to engage the bottom of said recess in said table and support said bottom plate at-alccation above the bottom of said recess.

8. In apparatus for cutting miters on work pieces such astrim strips and stop strips for doors or the like, a workholder adapted to be supported horizontally on a work table, said workholder comprising a plate formed in the shape of an isosceles'trapezoid having a Pair of parallel sides of unequal length and a pair of angular sides, said I angular sidesbeing inclined at angles of 45 with respect to the longer one of said parallel sides, adjustable locating means projecting from the bottom surface of said plate for' cooperation with the work table to position said workholder in predetermined position relative to the worktable, loc ng s u e on s id plate an x ending thereabove, projecting structure on said plate facingsaid ,7 locating structure and spaced a predetermined distance therefrom, and resilient biasing structurecarried bysaid projecting structure and facing the adjacent said locat- V ing structure for cooperation with said locating structure to hold the Work piece thereb'etween, said resilient-biasing structure'including a resiliently'supported cam 'surface normally spaced from said cooperating locating structure a' distance less than the corresponding dimension of the work piece to be inserted therebetween, said cam surface being curved downwardly from thettop of the resilient biasing structure into the work-receiving recess formed between said projecting structure and said adjacent locating structure so that the workpiece may be readily inserted and withdrawn from the top of said workholder. 7

9. A workholder according toclaim 8 wherein said locating structure is positioned adjacent the shorter one of said parallel sides and said resilient biasing structure is positioned adjacent the longer one of said parallel sides.

10. A workholder according to claim 8 whereinsaid locating structure is positioned adjacent the longer one of said parallel sides and said resilient biasing structure is positioned adjacent the shorter one of'said parallel sides.

11. A workholder according to claim 8 wherein the upper surface of said plate includes spaced raised portions adjacent the angular sides thereof for engaging the bottom of the work.

i References Cited in the file of this patent UNITED STATES PATENTS