US3345079A - Spring retainer for power-operated tool - Google Patents

Description

Oct. 3, 1967 f 3,345,079

SPRING RETAINER FOR POWER-OPERATED TOOL- J. L. WICKHAM Filed 001:. 21, 1965 Q INVENTOR JOHN L. WICKHAM ATTORNEY United States Patent .0

3,345,079 SPRING RETAINER FOR POWER-OPERATED 'roor.

John L. Wickham, Baltimore, Md., assignor to The Black ABSTRACT OF THE DISCLOSURE A power-operated tool is provided with an improved spring retainer. The retainer is generally in the form of a coil spring. One end of the coil spring is mounted on the barrel of the tool. The other end has at least one loop formed with a portion extending radially inwardly. This inwardly extending portion engages an annular shoulder on a suitable tool element, such as a chisel, which is received in the barrel of the tool. Thus the chisel is retained against ejection out of tool during its operation. One end of the loop is received back underneath itself, thereby improving the resiliency of the coil spring and the retention of the chisel.

Brief summary of the invention The object of the present invention is to provide a spring retainer which has three advantages: (1) an improved resiliency; (2) an improved retention; and (3) a facility for quick removal.

In accordance with the invention, the improved spring retainer is provided with substantially a complete coil or convolution between the end of the barrel and the loop portion of the retainer which engages the chisel, with the end of the loop being received back underneath itself, thereby improving its resiliency and its retaining function.

These and other objects of the present invention will become apparent from a reading of the following specification, taken in conjunction with the enclosed drawings, in which:

Description of the drawings FIGURE 1 is a perspective of the improved spring retainer;

FIGURE 2 shows the manner in which the spring retainer is threadably mounted on the barrel of a poweroperated tool for retaining a mufller-cutting chisel, the tool and the chisel being shown in broken lines;

FIGURE 3 is an enlarged top plan view of the spring retainer, looking down on the loop portion thereof, showing the manner in which the loop is tucked back (or received back) underneath itself;

FIGURE 4 is an end elevation;

FIGURE 5 is a side elevation; and 7 FIGURE 6 shows, first, the manner in which the retainer preferably engages threads formed on the barrel of the tool; secondly, the manner in which a portion of the loop engages a collar on the chisel to retain the chisel in the tool; and thirdly, the preferred use of two complete convolutions between the loop and the end of the barrel.

Detailed description 3,345,079 Patented Oct. 3, 1967 to threadably engage threads 12, see FIGURE 6, formed manner, the spring retainer is seated on the too]. To facilitate its threaded engagement, a hook 15 is formed on its end thereof for engagement by the operator.

The convolutions 11 terminate forwardly of the barrel in a loop 16, see FIGURE 3. This loop 16 has an inward portion 17 (directed radially-inwardly of the convolutions) which engages a collar 18 on the chisel 19 so as to retain the latter against ejection out of the barrel during the operation of the tool. This inward portion 17 of the loop is movable radially away from the chisel so as to facilitate a manual removal of the chisel from the barrel of the tool.

In the improved spring retainer 10 of the present invention, and unlike the prior art and prior commercial practices, the end 20 of the loop is received back underneath itself as shown more clearly in FIGURES 1 and 3. The end 20 of the loop may be tucked underneath itself, as shown in FIGURE 3, or it may first pass over itself and then be tucked underneath, if desired. Also, substantially one, and preferably two complete convolutions, see

FIGURE 6, are provided between the end of the loop and the end of the barrel.

With this arrangement, the objects of the invention are fulfilled. The spring retainer has improved resiliency and improved retention of the chisel, yet facilitates a quick removal of the chisel from the tool.

In one prior commercial practice, the end of the loop is brought all the way back to one of the first convolutions on the barrel, and while providing adequate retention, nevertheless substantially detracts from the resiliency of the retainer. Good resiliency of the retainer is desirable during the operation of the tool; otherwise the retainers tend to fall prematurely. In most prior commercial practices, the convolutions terminate forwardly of the barrel directly in the end loop which engages the collar on the chisel. This does not have good retaining power and hence is undesirable.

Obviously, many modifications may be made without departing from the basic spirit of the present invention; and accordingly, within the scope of the appended claims, the invention may be practiced other than has been specifically described herein.

I claim:

1. The combination with a power-operater tool, of a spring retainer for a tool element mounted in a barrel portion of the tool, said spring retainer having means engaging the barrel of the tool for seating said spring retainer on the tool, said spring retainer having convolutions terminating forwardly of the barrel in a loop, the loop having a portion thereof formed radially inwardly of the convolutions for normally engaging a cooperating portion of the tool element, thereby to retain the tool element against ejection out of the barrel during operation of the tool the portion of the loop engaging the tool element being movable radially away from the tool element to facilitate manual removal of the tool element from the barrel of the tool, and the end of the loop being received back underneath itself, thereby improving the resiliency of said spring retainer and the retention of the tool element.

2. The combination with a power-operated tool, of a spring retainer for a tool element mounted in a barrel portion of the tool, saidspring retainer comprising a series of convolutions threadably engaging the barrel of the tool, thereby seating said spring retainer on the tool, the convolutions terminating forwardly of the barrel in a loop, the loop having a portion thereof formed radially inwardly of the convolutions for normally engaging a cooperating portion of the tool element, thereby to retain the tool element against ejection out of the barrel during operation of the tool, the portion of the loop engaging the tool element being movable radially away from the tool element to facilitate manual removal of the tool element from the barrel of the tool, the end of the loop being received back underneath itself, and substantially one complete convolution between the end of the barrel and 4 the end of the loop which is received back underneath itself.

References Cited UNITED STATES PATENTS 1,176,343 3/1916 Christiansen 279-19.1 1,796,487 3/1931 Stevens 2.7919 2,051,670 8/1936 Anton 2671 2,445,551 7/1948 Barry 27919.6

FOREIGN PATENTS 324,558 8/ 1920 Germany.

ROBERT C. RIORDON, Primary Examiner.

Claims (1)

1. THE COMBINATION WITH A POWER-OPERATER TOOL, OF A SPRING RETAINER FOR A TOOL ELEMENT MOUNTED IN A BARREL PORTION OF THE TOOL, SAID SPRING RETAINER HAVING MEANS ENGAGING THE BARREL OF THE TOOL FOR SEATING SAID SPRING RETAINER ON THE TOOL, SAID SPRING RETAINER HAVING CONVOLUTIONS TERMINATING FORWARDLY OF THE BARREL IN A LOOP, THE LOOP HAVING A PORTION THEREOF FORMED RADIALLY INWARDLY OF THE CONVOLUTIONS FOR NORMALLY ENGAGING A COOPERATING PORTION OF THE TOOL ELEMENT, THEREBY TO RETAIN THE TOOL ELEMENT AGAINST EJECTION OUT OF THE BARREL DURING OPERATION OF THE TOOL THE PORTION OF THE LOOP ENGAGING THE TOOL ELEMENT BEING MOVABLE RADIALLY AWAY FROM THE TOOL ELEMENT TO FACILITATE MANUAL REMOVAL OF THE TOOL ELEMENT FROM THE BARREL OF THE TOOL, AND THE END OF THE LOOP BEING RECEIVED BACK UNDERNEATH ITSELF, THEREBY IMPROVING THE RESILIENCY OF SAID SPRING RETAINER AND THE RETENTION OF THE TOOL ELEMENT.

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