US1478760A - Sewing machine - Google Patents

Description

' Dec. 25,1923, 1,478,760

F. A. REECE SEWING MACHINE Original Filed June 14, 1919 2 Sheets-Sheet 1 Dec. 25, 1923. 7 1,4783% F. A. REECE SEWING MACHINE Original Filed June 14, 1919 2 Sheets-Sheet 2 Patented Dec. 25, 1923.

UNITED STATES PATENT OFFICE.

FRANKLIN A. REECE, OF CHESTNUT HILL, MASSACHUSETTS, ASSIGNOR TO THE REECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

SEWING MACHINE.

Original application filed June 14, 1919, Serial No. 304,223. Patent No. 1,424,851, dated August 8, 1922. Divided and this application filed January 26, 1922. Serial No. 531,996.

To all whom it may concern:

Be it known that I, FRANKLIN A. Brown, a citizen of the United States, residing at Chestnut Hill, county of Middlesex, State of Massachusetts, have invented an Improvement in Sewing Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to sewing machines of that type in which the under thread mechanism is in the form of a rotary hook constructed to take a loop of the upper or needle thread and cast it about a bobbin case containing a bobbin carrying the under thread thereby to interlock the needle thread loop with the under thread.

In the operation of sewing machines of this type it is important that the loop of needle thread should pass freely around the bobbin-case without being cut thereby, and it is the object of my present invention to provide an improved construction which will permit the sewing machine to operate at a very high speed without danger that the loop of needle thread will become caught on any projections or shoulders formed on the bobbin-case while said loop is being cast about the bobbin.

WVhile my invention might be embodied.

in various sewing machines in which the under thread mechanism is in the form of a stationary bobbin and rotary hook, I have herein chosen to illustrate it as it would be applied to a buttonhole sewing machine, such as is shown in my co-pending application Se. No. 280,704, filed March 5, 1919, but inasmuch as the invention relates simply to the under thread mechanism, I have not deemed it necessary to show the complete bottonhole sewing machine.

In the drawings, Fi 1 is a front view of the underthread mec anism of a buttonhole sewing machine such as illustrated in my co-pending application and having my present improvements applied thereto;

Fig. 2 is a top plan view of Fig. 1;

Fig. 3 is a side view;

Fig. 4 is an enlarged front view of the bobbin-case and rotary hook;

Fig. 5 is a top plan view of Fig. 4.

1 indicates part of the frame of a sewin machine which supports the under thread mechanism and which is situated beneath the bed plate indicated by the dotted line 2, Fig. 1. carries the upper eye-pointed needle, said needle being situated above the work and controlling the upper or needle thread. 26 indicates the throat-plate which is carried by the frame 1 and has the sewing opening 25 therein through which the needle 4 passes when it makes its penetrating thrust. Since the sewing machine herein shown is a buttonhole sewing machine, this. throat-plate 26 is illustrated as provided with a slit 27 to receive the knife which cuts the button hole in the goods.

The ,under thread mechanism is of the familiar type which comprises a stationary bobbin-case 5 adapted to receive a bobbin holder 6 in which the bobbin carrying the under thread is placed. Said bobbin holder is retained on an axial stud extending from the bobbin-case and is locked thereon by means of the usual spring-pressed locking lever 8. The rotary hook which takes the loop of needle thread and passes it about the bobbin-case is indicated generally at 9, said hook being carried by a short shaft 10 jour-' naled in bearings 11 formed on the frame 1. This shaft 10 is driven from a driving shaft 14 by means of intermeshing gears 12 and 13 that are fast on the shafts 10 and 14, respectively. Said gears are herein illustrated as two-to-one gears so that the hook will make two rotations for each rotation of the shaft 14. The shaft 14 is connected with the needle-actuating mechanism in any usual way so that it has one rotation for each reciprocation of the needle and, therefore, the hook will rotate twice for each reciprocation of the needle, all as shown in my said co-pending application. This hook member 9 is provided with the usual finger 15 which is constructed so that as it passes the upper center, it will engage the loop 16 of needle thread, as shown in Fig. 4, and by its rotation will cast said loop about the bobbin-case. The bobbin-case is provided with a recess 17 in its front face near its upper side in which is loosely received a positioning projection 18 carried b an arm 19 that is secured to the frame 1. e urpose of this positioning projection 18 1s to hold the bobbin-case from rotation while the machine is in operation.

3 indicates the needle bar which tion 18.

The parts thus far described are or may be all as usual in sewing machines of this type and as each loop 16 of needle thread is cast around the bobbin-case one leg of the loop is required to pass between the projection 18 and the walls of the recess 17 It is the object of my present invention to provide a construction which will obviate any possibility of the needle loop becoming caught while passing around the projection 18 even when the machine is runmng at extremely high speed.

The rotary movement of the hook is anticlockwise, Fig. 4, and the frictional engagement between the hook and the bobbin-case tends t turn said bobbin-case in the same direction and thereby holds the wall 28 of the recess 17 against the projection 18, as shown in Fig. 2. This contact between the projection 18 and the wall 28 tends to interfere with the free passage of one leg of the needle loop between said parts, especially when the shuttle is operating at a high speed. To prevent any such interference, I have provided novel means which acts on the bobbin-case just as the needle loop is to be passed around the projection 18 and moves said bobbin-case back slightly so as to open a space between the projection 18 and the wall 28, thereby allowing the loop of needle thread to freely pass said projection. The bobbin-case is provided with a projection 29 which is acted on by a finger 30 carried by a rock-shaft 31, and means are provided for turning the rock-shaft to give the finger a slight downward movement just after the loop of needle thread has passed said projection 29 and before it reaches the projec- The rock shaft 31 is carried in a suitable bearing 61 formed on the frame 1 and has fastathereto at its inner end another arm 32 which is adapted to be engaged by acam 33 that is fast on the shaft 14. The rook-shaft 31 is acted on by a spring 34 which holds the arm 32 in engagement with the cam 33. Said cam 33 has a high portion and a low portion, the low portion extending sli htly more than half way around the cam. en the arm 32 is in engagement with the low portion of the cam 33, as indicated in Fig. 1, said arm 30 will be separated slightl from the projection 29, and this is the position of the parts while the loop is being passed around the bobbin-case and until after said loop has passed the projection 29. The space thus provided between the arm 30 and the projection 291s sufficient to permit the loop of needle thread to freely pass the arm 30. After the needle loop has passed said projection 29 and arm 30, then the high portion of the cam 33 acts on the arm 32 and turns the rock-shaft 31 sli htly thereby moving the arm 30 downwardly to a slight extent and during such downward movement the arm 30 engages the projection 29 and turns the bobbin-case slightly in a clockwise direction. Such turning -movement is sufficient to separate the projection 18 from the wall 28 of the notch 17 so that the loop of needle threadwill pass freely around theprojection without being caught thereon.

With this improvement the sewing machine can be run at a very high speed without danger of the needle thread being caught on any projections on the bobbin-case or subjected to any jerky action such as would result if it had to be drawn around the projection 18 While the latter was in contact with the wall 28 of the recess 17.

This application is a division of my application Se. No. 304,223, filed June 14, 1919 on which patent No. 1,424,851 dated August 8th, 1922 was issued.

While -I have illustrated a selected embodiment of the invention, I do not wish to be limited to the constructional features shown,

I claim:

In a sewing machine, the combination with an eye-pointed needle, of a non-rotatable bobbin case, a rotary hook for taking a loop of needle thread and casting it about the bobbin case, said bobbin case having a recess on its front face, a positioning arm.

havin a projection to enter said recess and hold t e bobbin case from rotation, said bobbin case having a rounded protuberance on its front face, a driving shaft for rotating the hook, a rock shaft extending parallel to the driving shaft, a face cam on the driving shaft, an arm fast on the rock shaft and enaging said cam, a spring acting on the rock shaft to hold the arm in engagement with the cam, a finger fast on the rock shaft and adapted to engage said protuberance, the cam-actuated movement of the rock shaft causing the finger to move the bobbin case backwardly as the thread is drawn over the positioning projection.

In testimony whereof, I have signed my name to this specification.

FRANKLIN A. 'REECE,

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