US 3670678 A
A roller foot for sewing machines comprising a support and a feed roller secured to said support and inclined relative to the path of needle movement, said feed roller having a race ring that is connected to an inner disk by way of a ball bearing, while the inner disk is connected to said support by a releasable positive force transmitting connection and means, such as a screw that secures the connection.
Claims available in
Description (OCR text may contain errors)
[ 51 June 20, 1972 United States Patent Ziegler  References Cited UNITED STATES PATENTS  ROLLER-FOOT FOR SEWING MACHINES  lnventor:
Hans Ziegler, Kaiserslautem, upper Palatinate, Germany mm .mw WW 9 3 9 H 4 Primary Examiner-Patrick D. Lawson Attorney-Robert H. Jacob 22] Filed:
(21] Appl. No.:
ABSTRACT  Foreign Application Priority Data A roller foot for sewing machines comprising a support and a feed roller secured to said support and inclined relative to the path of needle movement, said feed roller having a race ring May 6, 1970 Germany......................P 70 17 001.3
.....ll2/235 that is connected to an inner disk by way of a ball bearing, 29/00 while the inner disk is connected to said support by a releasa- Int. Cl.
 Field of 1 12/235 240 ble positive force transmitting connection and means, such as a screw that secures the connection.
3 Claims, 2 Drawing Figures PATENTEDJum m2 3. 670,678
I NVENTOR: HAM) 2/544 4 ROLLER-FOOT FOR SEWING MACHINES BACKGROUND OF THE INVENTION The invention relates to a roller foot for sewing machines. More in particular the invention is concerned with a roller foot for machines having a support to which the feed roller is secured, joumalled to the support in a manner that it is inclined relative to the path of needle movement, and in which a race ring is connected with an inner disk by way of a ball bearing.
With known roller feet of this type either the inner disk and the support are formed as a unit, or they are made in two parts and are threadedly connected with each other. The nonreleasable construction has the shortcoming. that as the running surface of the feed roller wears down, the entire roller foot must be replaced. For machines with roller foot drive this requires a considerable expense when the bearing for the drive pinion is built into the support.
When the feed roller is mounted on the support by means of screws the roller can be exchanged in a simple manner. The use of strong screws required due to the forces that develop results in relatively great axial structural length at the location of the connection between the feed roller and the support. As a result the lateral working space available for handling the material is considerably reduced.
SUMMARY OF THE INVENTION In accordance with the invention the advantages of the two embodiments are to be combined without having to adopt their shortcomings. This is accomplished in accordance with the invention in that the inner disk is secured to the support by way of a releasable positive force transmitting connection, a means that insures the maintenance of this connection. The positive connection provides the possibility of realizing a construction of an extremely small structural length.
A suitable construction design of the connection provides that the inner disk has a projection with a wedge shaped, upwardly open recess which receives the conforming wedge shaped end of the carrier or support.
Optimum advantages of the positive connection effect are obtained by locating the connection in the area below the roller axis of the feed roller. Owing to the pressure load from the pressure foot spring applied to the roller foot during the operating condition, the part of the inner disk disposed above the positive connection is firmly pressed against its engagement surface with the support or carrier.
BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is illustrated in the drawing in which,
FIG. I is a front view of the roller foot partly in section, and
FIG. 2 is a side view.
The block 2 is secured to the presser bar I of the sewing machine. The roller foot is threadedly mounted in a known manner by screw 5 on the block 2 by means of lug 3 and support 4. The feed roller 7 is secured to the downwardly extending arm 6 of the support 4.
The feed roller comprises inner disk 8 of two disk parts 9 and I0 and race ring 1 1. These components together with the balls 12 constitute a ball bearing.
The disk parts 9 and 10 are centered by means of a centering member 13 in disk part 9 and a corresponding bore 14 in disk part 10 and connected with each other by flat head screws 15. The tolerance for bearing balls 12 is determined by spacing screws 16 that are threaded into the disk part 9 and press against disk part 10.
The disk part 10 is provided externally of its lower half with an extension 17 that has a horizontally oriented groove 18 which is open at the top. The wedge shaped end 19 of the arm 6 engages the groove 18. In this manner a positive connection is provided.
A fiat head screw 20 serves to secure this connection against unintentional releasing of this connection. It is threaded from arm 6 into the disk part 10.
As the roller foot is lowered onto the sewing material the downwardly directed force of the spring (not illustrated) of the presser bar 1 effects a tilting moment of the feed roller 7 about the contact line of the race ring II with the material being sewn. Thereby the feed roller 7 supports itself by means of the surfaces of the groove 18 against the wedged end 19 of the support 4 and the aforementioned tilting moment presses the disk part 10 against arm 6.
Having now described the invention with reference to the illustrated embodiment the scope of protection sought by letters patent is set forth in the appended claims.
1. Roller foot for sewing machines having a support member on the presser bar of the machine and a feed roller secured to the support member, said feed roller being inclined with respect to the path of the needle and having an inner disk, a race ring connected to said inner disk with bearing balls therebetween and defining a ball bearing therewith, a flat member mounted on said support member and presenting a centering member, a recess provided on said inner disk for receiving said centering member and fastening means between said support member and said inner disk securing said flat member to said support member.
2. Roller foot in accordance with claim 1, including an extension on said inner disk presenting a V-shaped groove open at the top and a wedge shaped end on said support for engagement with said groove.
3. Roller foot in accordance with claim 2, where said V- shaped groove is disposed in an area below the axis of the roller of said feed roller.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5670678 Dated June 20, 1972 Inventor(s) Hans Ziegler It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:
Title page, 001. 1
Item (50) P 7O 17 001.5 should be G 7O 17 001.5
Signed and sealed this 17th day of October 1972.
ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents