US3071091A

US3071091A - Guide bed for sewing machines

Info

Publication number: US3071091A
Application number: US85562A
Authority: US
Inventors: Loreen H Erbland
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-01-30
Filing date: 1961-01-30
Publication date: 1963-01-01
Anticipated expiration: 1980-01-01

Description

Jan. 1, 1963 L. H. ERBLAND GUIDE BED FOR SEWING MACHINES Filed Jan. 50, 1961 INVEN TOR. LOREEN H. ERBLAND ROBERT J. PATCH ATTORNEY FIG. 5

United States Patent Ofitice 3,871,091 Patented Jan. 1, 1963 3,071,891 GUIDE BED FQR SEWING MACHWES Loreen H. Erbland, 1525 N. Van Ness St, Santa Ana, (Ialif. Filed Jan. 38, 1961, Ser. No. 85,562 3 Claims. (Cl. 112-268) The present invention relates to guide beds for sewing machines, and more particularly to sewing machine beds provided with arrangements for guiding material relative to the bed and relative to other portions of the material as the material moves across the bed and through the sewing mechanism.

It is an object of the present invention to provide sewing machine mechanism which will give a visual indication of the accuracy of the formation of the seam, both relative to the bed and relative to other portions of the material.

Another object of the present invention is the provision of sewing machine mechanism which will permit quick and accurate formation of sewed seams.

Finally, it is an object of the present invention to provide sewing machine structure which will be quick and easy to manufacture, which can be inexpensively incorporated in new sewing machines or by conversion in old sewing machines, and which will be easy to operate, dependable, rugged and durable in use.

Other objects and advantages will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a fragmentary plan view of the region of a sewing machine throat plate according to the present invention;

FIGURE 2 is a section on the line 22 of FIGURE 1 and showing the novel throat plate of the present invention in cooperation with the sewing mechanism of the machine; and

IGURE 3 is a View on the line 3-3 of FIGURE 1 and showing a further refinement of the present invention.

Referring now to the drawing in greater detail, there is shown sewing machine structure comprising a bed I having a horizontal upper working surf-ace 3. Bed it is in the form of the usual flat plate and has the usual opening 5 therethrough having a semi-circular end portion and bounded by a narrow shelf 7 on which rests a throat plate 8 of the usual shape. Fastening screws 9 removably secure throat plate 8 to shelf 7 in the usual way. As is also conventional, the upper surface of throat plate 8 is flat and horizontal and flush withthe rest of working surface 3, while fastening screws 9 are flat-headed and flush with working surface 3.

In the illustrated embodiment, the sewing mechanism is located at some distance inward of the outboard end of bed 1, and opening 5 extends all the way out to the outboard end. Accordingly, a slide cover plate ll of rectangular configuration is provided to fill opening 5 endwise outwardly of the outer straight edge of throat plate 8.

Throat plate 8 is provided with the usual needle aperture 13 therethrough, and also with elongated parallel slots 15 of ordinary configuration and arrangement. The usual work feed mechanism 17 terminates at its end in feed dogs 19 which have serrated upper surfaces and which are the same in number as slots 15 and extend upwardly through slots 15. This work feed mechanism is conventional and is disposed beneath working surface 3.

The usual vertical needle 21 is carried by needle bar 23 and extends downward through needle aperture 13, while a conventional presser bar (not shown) carries at its lower end the usual presser foot 25 which extends on either side of needle 21 and coacts with feed dogs 19 properly to position and advance the material.

All of the structure as described thus far is conventional and is no departure from the prior art.

The invention departs from the prior art, however, in that throat plate 8 is light-penetrable, at least adjacent slots 15 and needle aperture 13. Preferably, throat plate 8 is transparent and is made of glass or hard plastic. Fabrication from hard plastic is easier than fabrication from glass, and a hard plastic throat plate is less subject to breakage than a glass throat plate. Moreover, although hard plastic is more subject to scratching than is glass, such scratching is not detrimental to the present invention, for although such scratching decreases the transparency of the material of the throat plate, it does not substantially alter the light-penetrability of the material. As will be pointed out later, it is the light-penetrability of the material that is the important feature of throat plate 8, and a transparent throat plate is preferred simply because a transparent material is the most highly lighttransmissive.

An electric light source 27 is a vital feature of the present invention in combination with the light-penetrable portion of throat plate 8 adjacent slots 15 and needle aperture 13. Light source 27 comprises an electric light bulb 29 disposed beneath working surface 3 closely adjacent slots 15 and needle aperture 13. Bulb 29 is replaceably mounted in a socket 31 carried by a bracket 33 including a reflector 35 which is upwardly concave and is so disposed as to reflect light emitted downward from bulb 29 back up toward slots 15 and needle aperture 13. Bracket 33 is held in place on the underside of the plate comprising bed 1 by means of attachment screws 37 passing through the bed plate.

The purpose and function of the essential elements of the invention will now be apparent. When throat plate 8 with its light-penetrable portion is in position as shown and electric light source 27 is turned on, light will shine up through throat plate 8 from below at least adjacent needle aperture 13 and slots 15. Most fabrics are to some extent light-transmissive, at least sufficiently so that a strong light canto some degree be seen to shine through them from the side opposite the viewer. Accordingly, it will be appreciated that when such fabric is run between feed dogs 19 and presser foot 25 in multiple layers, hidden edges or hems or seams or lines of stitching will show up in silhouette and their location can be determined even though they "do not appear on the uppermost layer of fabric. In this way, the line of stitching that is being formed can be properly oriented relative to such hidden seams or lines and can be made parallel thereto at selected distances or can be made precisely to coincide with desired portions of any hidden layer of fabric.

Another desirable feature of the present invention is not restricted to operation with multiple layers of fabric. This further feature of the invention arises from the fact that when thread of the same color as the workpiece is being applied by a sewing machine, the resulting line of stitching is often not readily visible by reflected light incident from above. But the applied line of stitching is distinctly apparent when light shines through the material from below, for the line of stitching provides in effect a relatively light-impervious line along the fabric that shows up as a distinctively darker line across the field of light from below.

In its preferred form, throat plate 8 is not light-trans missive over its entire area, but only adjacent slots 15 and needle aperture 13. Spaced from needle aperture 13 and slots 15, throat plate 8 preferably has an opaque portion which in the preferred form of the invention is a silvered portion 39. Broadly, silvered portion 39 c mprises a portion of throat plate 8 which is highly reflective on its underside. If throat plate 8 is made of glass, then silvered portion 39 may be applied by silvering in the usual manner to the upper surface of throat plate 8, or by front silvering on the lower surface of throat plate 8. Application of the reflective layer to the undersurface of throat plate 8 has the obvious advantage that it is not nearly so subject to wear as if it is on the upper surface as shown. Of course, the highly reflective surface may be applied to throat plate 8 by other means such as vapor deposition of metals such as aluminum, or in any of a variety of other ways. If throat plate 8 is hard plastic, then the highly reflective layer may be applied to either face by a variety of methods including the application of thin foil, etc. Of course, it will be understood that the purpose of the highly reflective surface is to reflect light rather than to reflect precise images, so that the reflective surface need not at all be an optical surface.

The highly reflective undersurface portion of throat plate 8 performs two functions: (1) because it is opaque, it permits light source 27 to be positioned considerably closer to the sewing mechanism without shining directly in the operators eyes; that is, it masks light source 27 to prevent glare; and (2) because it is highly reflective downward, it increases the intensity of illumination below working surface 3 and increases the reflected light which finds its way back up through the light-transmissive portions of throat plate 8. Of course, throat plate 8 could be made in the first place to be only the size and shape of its light-transmissive portions, but this arrangement is less preferred in that it would require modification of existing sewing machine bed structure in which the size and shape of opening 5 is fairly standard.

Another feature of the present invention which coo-perates to produce a result closely related to the result of the structure already described is shown adjacent the bottom of FIGURE 1 and in FIGURE 3 of the drawing. As is there shown, bed 1 is provided with an elongated recess 41 opening therethrough that extends laterally from the edge of the bed plate and opens into opening 5. Recess 41 has parallel straight edges, and a shelf 43 like shelf 7 runs along each edge of recess 41. A light-transmissive, preferably transparent, alignment plate 45 of glass or hard plastic rests on shelf 43 and completely closes recess 41 and has its upper surface as a part of and flush with the remainder of working surface 3. Plate 45 thus extends endwise of and for a considerable distance endwise beyond the lengths of slots 15. Plate 45 may be held to shelf 43 by screws (not shown) or it may have sliding tongue and groove engagement with the side edges of recess 41, or as in the illustrated embodiment it may be made of hard plastic of limited resiliency and simply snap into place. 7

Plate 45 is provided with indicia 47 which are elongated in the direction of the length of slots and are disposed a considerable distance endwise beyond slots 15. In the illustrated embodiment, they are parallel to slots 15. They are spaced apart laterally of the extended length of slots 15, that is, they are spaced apart in a direction perpendicular to slots 15 and are disposed on either side of and are parallel to a prolongation of the length of slots 15. Preferably, indicia 47 are parallel straight lines. They are light-impenetrable and they are preferably formed on plate 45 by marking as with indelible paint or ink in long recesses on the upper surface of plate 45, so that they will not readily wear off.

A second electric light source 49 is provided closely adjacent but below indicia 47 and below working surface 3, comprising a second electric light bulb 51 in a socket 53 on a bracket 55 having a reflector 57 to direct light emitted downward from bulb 51 back up to indicia 47, and attachment screws 59 to hold bracket 55 to the underside of the plate comprising bed 1.

Plate 45 functions in a manner quite similar but distinguishable from the manner in which the light-transmissive portion-s of throat plate 8 function. Specifically, indicia 47 now play the part that was played by a hidden edge or seam in connection with throat plate 8. As lightpenetrable fabric passes across working surface 3, downward as seen in FIGURE 1, from needle aperture 13 over alignment plate 45, the line of stitching produced by needle 21 shows up first on the light-transmissive portions of throat plate 8 and then across alignment plate 45 as a relatively dark line across the light field of the illuminated fabric. At the same time, the light from below plate 45 shining up through plate 45 makes indicia 47 show up as dark lines as seen through the fabric that covers plate 45. The dark line of the stitching can then be aligned with any selected portion of indicia 47 so as accurately to orient the fabric and the stitching as desired. In other words, indicia 47 provide a guide for the formation of the seam even though these indicia are invisible when covered by the fabric as seen in reflected light incident from above, for the light from below brings them out even through the fabric. For this reason, it is preferred that indicia 47 be disposed on the upper surface of plate 45 rather than on the undersurface, so that they are as close as possible to the fabric which covers them and accordingly cast a. sharper shadow on the fabric than if they were spaced from the fabric by the thickness of plate 45.

From the above discussion of the light-transmissive portions of throat plate 8 and alignment plate 45, it will be obvious that the aim of these members is to make sure that a maximum of light is transmitted upward through the fabric which covers them, over a relatively broad field, so that the illuminated field will appear as light as possible in contrast to the darker lines of stitching or of indicia 47. Therefore, it will be appreciated that one desirable form of the light-transmissive portions of throat plate 8 and of alignment plate 45 is that they be frosted on their underside so as to make sure that the light that is transmitted upward through them provides a uniformly bright field. Thus, although the material of these members may be transparent, in one desirable form the material as a whole may be translucent because frosted.

From a consideration of the foregoing description, it will be obvious that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with preferred embodiments, it is to be understood that modifications and variations other than those specifically described above may be resorted to without departing from the spirit and scope of the invention, as will be readily understood by those skilled in this art. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

What is claimed is:

1. In a sewing machine having a bed having an upper horizontal working surface, work feeding mechanism below said surface and including at least one feed dog, said surface having at least one horizontally elongated slot opening therethrough through which said at least one feed dog extends; the improvement comprising the bed being light-penetrablefor a substantial distance endwise of said at least one elongated slot, light-impenetrable indicia on a light-penetrable portion of the bed and disposed a substantial distance from and endwise of said at least one slot, and an electric light source disposed below said surface and adjacent said indicia.

2. Apparatus as claimed in claim 1, there being a plurality of said indicia spaced apart in a direction perpendicular to a prolongation of the length of the slot and extending on both sides of said prolongation of the length of the slot.

3. In a sewing machine having a bed plate having an upper horizontal working surface, the bed plate being provided with an opening adjacent the sewing mechanism, a throat plate secured in assembly with the bed plate and having an upper surface substantially flush with the upper 5 6 surface of the bed plate, work feeding mechanism below metal coating on the under surface thereof exposed to light said surfaces and including at least one feed dog, the from and directly above said electric light source. throat plate having at least one opening therethrough through which said at least one feed dog extends, the Regelemes Cited in the file of fills Patent throat plate being light-penetrable over a substantial area thereof adjacent to said at least one opening, and an UNITED STATES PATENTS electric light source disposed below said surfaces and ad- 2 ireeman g g jacent said at least one opening; the improvement comprisyres c ing a portion of the throat plate spaced from said at least REI N PATENT one opening being ofthe light-penetrable material of the 10 6,384 Great Britain Man 25, 1905 rest of the throat plate but having a highly light reflective

Claims

1. IN A SEWING MACHINE HAVING A BED HAVING AN UPPER HORIZONTAL WORKING SURFACE, WORK FEEDING MECHANISM BELOW SAID SURFACE AND INCLUDING AT LEAST ONE FEED DOG, SAID SURFACE HAVING AT LEAST ONE HORIZONTALLY ELONGATED SLOT OPENING THERETHROUGH THROUGH WHICH SAID AT LEAST ONE FEED DOG EXTENDS; THE IMPROVEMENT COMPRISING THE BED BEING LIGHT-PENETRABLE FOR A SUBSTANTIAL DISTANCE ENDWISE OF SAID AT LEAST ONE ELONGATED SLOT, LIGHT-IMPENETRABLE INDICIA ON A LIGHT-PENETRABLE PORTION OF THE BED AND DISPOSED A SUBSTANTIAL DISTANCE FROM AND ENDWISE OF SAID AT LEAST ONE SLOT, AND AN ELECTRIC LIGHT SOURCE DISPOSED BELOW SAID SURFACE AND ADJACENT SAID INDICIA.