US2720852A - Shoe sewing machines - Google Patents

Description

Oct. 18, 1955 HAY 2,720,852

SHOE SEWING MACHINES Filed May 18, 1953 igza 24 Z Z6 [7111612 for Dana P Hay 6 By hisAztorlzey United States Patent SHOE SEWING MACHINES Dana P. Hay, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application May 18, 1953, Serial No. 355,592 3 Claims. (Cl. 112-55) The present invention relates to improvements in hook needle shoe sewing machines and more particularly to means for preventing displacement of a needle threading looper from proper operating position in the main supporting frame of a shoe sewing machine, by the use of which means greater accuracy of looping is obtained and other beneficial advantages are gained, the achievement of which constitute the objects of the invention.

The invention is herein illustrated as embodied in a machine similar to that disclosed in United States Letters Patent No. 1,971,575, granted August 28, 1934 and No. 2,219,933, granted October 29, 1940 both upon application of A. R. Morrill. The machine of the patents is provided with a hollow main frame having forwardly projecting vertical side walls within which are mounted certain of the stitch forming devices including a curved hook needle and a looper for laying the thread in the hook of the needle.

In the patented machine the looper is fixed to a movable support and is actuated by cam arms connected at separated points to the support. Each cam arm is pivotally connected to the looper support and oscillates to actuate the looper about the hooked end of the needle. The oscillating movement of each arm imparts a reciprocating movement to the looper support and also results in a slight movement transversely to the direction of reciprocation as a result of foreshortening action in the cam arm. To guide the looper support the forward end is slidably mounted between parallel bearing surfaces in the machine frame in its forwardly projecting portion but because of the transverse movement of the looper support these surfaces do not fit closely with the support and as a result excessive wear and inaccuracies of looping may occur under some conditions of adjustment.

According to one feature of the invention the looper is guided in its movement about the end of the needle by a block having a flat bearing surface mounted in the frame of the machine and arranged to prevent movement of the looper away from the end of the needle during the looping operation and co-operating with said bearing surface is a reversely bent resilient plate mounted at one end on the machine frame and at the other end beyond the reverse bend engaged with the looper support to prevent movement of the looper toward the needle. Preferably, the reversely bent plate is T-shaped, the central shank containing the reverse bend and the cross bar being adjustably secured to the machine frame. This feature of the invention comprises an arrangement in which the block acts as a spacer between forwardly projecting portionsof the frame and is clamped to a vertically swinging bracket, so that upon unclamping the spacer block it may be raised for affording convenient access to underlying parts without disturbing the position of the looper support or the reversely bent plate.

These and other features of the invention incorporated in the devices, combinations and arrangements of parts hereinafter described and claimed which, together with the advantages to be obtained thereby, will readily be understood from the following detailed specification taken in connection with the accompanying drawings, in which:

Fig. 1 is a view in right side elevation of the partly broken away forwardly projecting parts of a shoe sewing machine head embodying the features of the present invention;

Fig. 2 is a sectional view in illustrated in Fig. 1;

Fig. 3 is a detail sectional view in left side elevation of the looper, looper support and its front bearing in the machine frame; and

Fig. 4 is a detail plan view of the reversely bent resil ient looper support plate shown in the other figures.

The shoe machine illustrated in the drawings, except as hereinafter described, is substantially the same in construction and mode of operation as that described in the patents above referred to. The sewing head of the machine has a frame formed with two upwardly projecting side walls 2 and is arranged to be mounted upon a supporting column (not shown) with operating mechanisms and stitch forming devices including a curved hook needle 4 and a looper 6 actuated by cam driven connections carried between the side walls of the frame. The looper 6 is mounted at the forward end of a flat Y-shaped support 8 to which the looper is fixed at an angle to the plane of the support, the lower end of the looper projecting toward and intersecting a circular path through which the needle oscillates during sewing operations.

The needle in its work penetrating position is projected upwardly a short distance above the lower end of the looper in order that the thread carried by the looper may be laid with certainty in the hook of the needle. It is desirable to have the position of the looper accurately determined with relation to the needle and to this end a finished surface 10 on the looper support 8 slidingly engages a corresponding flat surface 11 on a spacing block 12 secured in the head frame of the machine between the side walls 2. The rearward ends of the looper support 8 are each pivotally connected at separated points by means of a universal joint to one of two independently operable spaced actuating arms 14 fulcrumed on a fixed shaft 16 in the frame side walls. Each actuating arm carries a cam roll 13 engaging a cam 20 on the sewing shaft, by means of which cam the arms are oscillated on the shaft 16 through arcs defining parallel planes to carry the looper in a circular path about the hooked end of the needle while in work penetrating position. The planes through which the arms 14 oscillate are at right angles to the hearing surfaces 10 on the looper support 8 and 11 on block 12.

Because of the oscillating movements of the arms 14 in planes at right angles to the bearing surfaces on the looper support and block, the rearward ends of the looper support move somewhat in a direction transverse to the bearing surfaces 10 causing the looper support to rock about the engaging surface 11 of the block 12. As a result, in the machine of the patents above noted the engaging surfaces of the looper support and spacing block are subject to excessive wear and it is difficult to arrange means for maintaining the surface 10 continuously in engagement with the bearing surface of the block, eX- cessive looseness between the bearing surfaces causing inaccurate movements of the looper in laying the thread in the needle hook, especially when the needle strokeis not adjusted with accuracy. Also, where waxed thread requiring heat during use is employed, it is necessary to transmit heat to the looper by conduction through contact of the looper support 8 with the surface 11 of the block 12. For this purpose the block 12 has an opening Within which is inserted an electrical heating cartridge 22. If the looper support is not in firm contact with the block the rate of heat conduction to the looper is greatly front elevation of the parts reduced so that time required to bring the machine if is obtained. 7 7 For pressing the looper supports into'firm contact with and against displacement from'the block 12 on the head frame of the machine at all times, in accordance with the present invention, the right side Wall 2 of the head frame has adjustably secured to itone end of a reversely bent resilient member in the form of a T-shaped plate 24 with the other end beyond the reverse bend in its central shank engaged by the under surface of the looper support 8 directly beneath the. block 12.' The crossbar of the T-shaped plate has two vertically alined slots 26 to receive a pair of clamp screws 28 passing through them and into threaded engagement with the forward edges of the side walls 2. The reverse bend, indicated at 29 in the plate 24 is located close totthe crossbar portion and between the crossbar and the other end portion of the central shank engaged by the looper support 8. In this Way an exaggerated yielding action in the central shank of the plate 24 is obtained while maintaining the looper support in firm contact with its hearing surface on the spacing block 12. Also, the plate 24 is constructed from sheet metal having suitable heat treatment to accentuate its yielding action.

The position of the T-shaped plate is adjustable vertically on the head frame to maintain the bearing surface 10 continually in contact with the block 12 regardless of the oscillating movements of the arms 14, the central shank of the plate yielding slightly at the reverse bend as the bearing surface 10 is tilted with respect to the surface on the block. This adjustment is obtained by loosening the screws 28 and shifting the crossbar until the proper position is reached. To prevent angular movement ofthe plate 24 during adjustment, the crossbar has a greater thickness than the central shank, an abrupt shoulder being formed at the joint between the crossbar and central shank. By reason of the greater thickness the crossbar fits into a guideway 30 formed in the righthand side wall of the machine head and engagement of the crossbar on the plate 24 with the guideway relieves the clamp screws 28 of sharing action, particularly if they become loosened during use.

It will be appreciated that a simple and effective displacement preventing plate is provided for the looper which is easily manufactured and readily adjusted. The yielding action of the plate 24 is relatively small but sufficient to press the looper support 8 against the block 12 at all times, The fact that the looper support bears againsta rigidly fixed block insures that the looper will not be raised from its proper. vertical position with respect to the hooked end of the needle at any time, although it may be lowered slightly as a result of tilting the support along the bearing surface 11 of the block 12. Thus, the movements of the looper support toward the needle are reduced to a minimum and the looper is never allowed to move vertically in an uncontrolledmanner away from the bearing surface of the block. Also, the plate 24 being mounted on the side wall 2, the spacing block 12 maybe removed from between the side walls without displacing the looper from operating position. Ability to remove the spacing block occasionally is desirable to provide convenient access to the underlying parts in the machine, the block normally being retained in clamped position between the side walls 2 by a bolt 32 passing through the side walls and the block. For convenience in supporting the block 12 while removed, it is a secured by screws 34 to a bracket 36 rotatably mounted on a hinge pin 38 passing through upstanding lugs on the side walls 2 of the main frame at the upper end of the bracket. After removing the bolt 32, the entire bracket with the spacing block may be swung upwardly away from the main frame in a desirable manner.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what isclaimed is: i

1. A shoe sewing machine having a main frame and stitch forming devices including a hook needle and a looper, a support to which the looper is fixed, independently operable actuating arms for said looper arranged to oscillate through arcs defining parallel planes and pivotally connected to the support at separated points to carry the looper about the hooked end of the needle, and a block in the frame having a flat bearing surface extending at an angle to the planes of the actuating arms, in combination with a reversely bent resilient member mounted at one end on the frame and engaged at the other end beyond the reverse bend with the'loopersupport for pressing the looper support against the bearing surface.

2. A shoe sewing machine having a main frame and stitch forming devices including'a hook needle and a looper, a support to which the looper is fixed, independently operable actuating arms for said looper arranged to oscillate through arcs defining parallel planes and pivotally connected to the support at separated points to carry the looper about the hooked end of the needle,

and a block in the frame having a flat bearing surface extending at an angle to theplanes of the actuating arms, in combination with a reversely bent resilient member for pressing the looper supportagainst the bearing surface, comprising a T-shaped plate having the reverse bend in one end of the central shank of the T close to the crossbar, the crossbar being adjustably secured to the machine frame, and the central shank of the T at its other end beyond the reverse bend being engaged with the looper support.

3. A shoesewing machine having a main frame and stitch forming devices including a hook needle and a looper, a support to which the looper is fixed, independently operable actuating arms for said looper arranged to oscillate through arcs defining parallel planes and pivotally connected to the support at separated points to carry the looper about the hooked end of the needle, and a block in the frame having a flat bearing surface extending at "an angle to the planes of the actuating arms, incombination with a reversely bent resilient member for pressing the looper support against the bearing surface, comprising a T-shaped plate having the reverse bend in one end of the central shank of the T close to the crossbar, the crossbar being adjustably secured to 'the machine frame, the central shank of the T at the other end beyond the reverse bend-being engaged with the looper support, the crossbar of theplate being of greater thickness than the central shank and fitting w'thin a guideway in the machine frame to prevent angular displacement of the crossbar.

2,647,478 Eastman Aug. 4, 1953 Merrill Aug. 28, 1934

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