US3392792A

US3392792A - Impact tool

Info

Publication number: US3392792A
Application number: US519583A
Authority: US
Inventors: Travis L Hunter
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-01-10
Filing date: 1966-01-10
Publication date: 1968-07-16
Anticipated expiration: 1985-07-16

Description

July 16, 1968 I T. L. HUNTER IMPACT TOOL Filed Jan. 10, 1966 3 Sheets-Sheet 1 T. L. HUNTER July 16, 1968 IMPACT TOOL 3 Sheets-Sheet :2

Filed Jan. 10, 196E 5/ Md j;

4770F/VEK1' T. L. HUNTER IMPACT TOOL 5 Sheets-Sheet 3 Filed Jan. 10, 196

i Z mm I WM M 1L. 4 NW w E\ w w fi &\ l i Q .1 H 3 3| N x p Q Qm United States Patent 3,392,792 IMPACT TOOL Travis L. Hunter, 5002 Persimmon St., Temple City, Calif. 91780 Filed Jan. 10, 1966, Ser. No. 519,583 3 Claims. (Cl. 173-102) ABSTRACT OF THE DISCLOSURE The tool employs a plurality of pistons disposed in a housing to actuate a laterally acting impacting member. In one embodiment the pistons directly strike a cap on the impacting member to thrust the latter laterally outward of the longitudinal axis of the housing. In an alternate embodiment a ball is disposed between the pistons and the impacting member to transmit the force of the pistons to the member.

This invention relates to the art of impact tools. More particularly this invention relates to impact tools for use in confined spaces.

Work of an impact nature is often performed in confined spaces. One example of such work is in the repair of damaged door panels of cars and trucks. These doors have relatively narrow cross-sectional dimensions defined by the space between the outside and inside panels of the door. When the outside panel is damaged, it has heretofore been the practice to insert a body pick, which is a long slender rod, through a water drain hole in the bottom of the door or through an end of the door. The pick is then manually operated to pry the damaged portion of the panel into substantially its original condition. Alternatively, a hole is drilled in the damaged section of the panel and a tool is placed behind the panel for prying or pulling the damaged portion into substantially its original condition. A third alternative is to remove the upholstery on the inside of the door and any necessary structural parts to expose the damaged section in order that it maybe expanded directly from within. The time consumed in both the preparation and the use of the tool is considerable. Moreover, results of such preparation, such as in the removal of upholstery, in effect extends the repair to include rectifying the preparation.

In many applications such as the aforementioned body art, space limitations have heretofore prohibited the use of power-actuated impact tools. The width of an automotive door provides an example. Unless the impact tool is of a limited transverse dimension, it cannot be used for it will interfere with the inner and outer panels of the door or structure within the door itself. In addition, such use requires a large opening for the tool to reach the damaged space because of the width of these tools. Moreover, the working area in a substantial number of cases is relatively remote from the point where simple ingress to such area is possible. The lateral dimensions in the working area combined with the distance of the working area from the point of ingress requires the use of a tool which acts laterally of its axis. Such a tool must also be rigid to avoid flexing and the concomitant loss of much of the impact force.

For ease of controlling the number of impacts on a workpiece, it is highly desirable for an operator to actuate an impact tool one impact at a time, i.e., to have a single impulse tool. However, it is also desirable in many instances to have a relatively large number of impacts per unit of time. The prior'art impact tools do not offer this flexibility of selection.

There are many other applications for impact tools for use in areas which have a limited working space thus reice quiring a relatively narrow and rigid tool having the actual impacting member acting laterally of the longitudinal axis of the tool. Such applications include riveting, chiseling and peening.

Briefly, this invention provides an impact tool capable of delivering a single discrete impact to a workpiece. This tool has a housing which includes a head and a bore. Mounted within the head is an impacting member which is operable to extend a portion of itself laterally outside of the head, and of the longitudinal axis of the housing. This member is biased inwardly towards the longitudinal axis of the tool. The impacting member is actuated by the action of at least one piston disposed within the bore. The pistons are capable of movement toward and away of the impacting member, but are biased away therefrom. Means are provided for moving the pistons towards the impacting member such that a portion of one of the pistons contacts the member and drives a portion thereof laterally of the longitudinal axis and outside of the head.

In its preferred form this invention contemplates the use of a housing having a longitudinal bore within which is slidably and fluid-tightly disposed a first or primary piston biased towards one end of the bore by means of a spring interposed between it and a secondary piston. This secondary piston is located in the bore in position to be contacted by the primary piston and is biased towards the primary piston by the action of a second spring. An impacting member is mounted in the other end of the housing, that is, spaced from the primary piston by the secondary piston, and is disposed such that it is capable of protruding through an outlet in the side of the housing upon being contacted by the secondary piston. This impacting member is biased such that it normally resides substantially within the housing.

Upon the admission of fluid pressure to the bore, the primary piston is thrust against the secondary piston which in turn contacts the impacting member, forcing a portion of the latter to protrude out the side of the housing. Preferably the primary piston is actuated by air pressure. In order for the primary piston, secondary piston and impacting member to easily return to their neutral positions, that is, the position wherein the impacting member is in an undistended or inactivated state, a first exhaust port is provided at the end of the housing closest to the fluid source. The primary piston being biased towards this end forces the air out of the exhaust port thus avoiding its compression. A second exhaust port is provided at a point relatively removed from the first exhaust port along the housing. This exhaust port serves as a means for air to escape as the secondary piston moves towards the impacting member and avoids the creation of a vacuum within the bore as the secondary piston moves away from such member and seeks its neutral or unactivated position after being impacted by the primary piston. Preferably, the tool operates in single discrete impacts initiated upon the admission of air to the bore by opening a valve; the valve must be closed before another impact is initiated.

One of the advantages of this invention resides in the capability of making the tool very thin and relatively long. For example, the housing, which defines the largest transverse dimension, has been made with a diameter of /8 of an inch. Smaller dimensions can be achieved. The length of the tool can be as long or as short as the operator desires by providing the housing in sections. These sections can be secured together by, for example, providing a male thread on one end of a section which engages a female thread on the end of another section. These dimensional features allow the tool to gain access to spaces which heretofore have been inaccessible to power operated tools. Such spaces include the aforementioned door 3 panels. Because the impacting member normally resides within the housing, there is no extension of the maximum transverse dimension. Thus the member does not interfere when gaining access to a working area through relatively confined spaces.

Another advantage of this invention is in its operating flexibility. An operator can actuate the impact tool to get a single discrete impact on a workpiece. Alternately, the operator can achieve a relatively large number of impacts in a unit of time by simply actuating the tool over and over again. However, the tool can be adapted for rapid automatic actuation by means well known in the art. So adapted, the impacting member will strike a workpiece over and over again without the necessity of the operator continuously actuating the tool.

These and other aspects, features and advantages of this invention will become more apparent from the following description, appended claims, and drawings in which:

FIGURE 1 is a view partly in cross section taken along the longitudinal axis of a preferred embodiment of this invention in which the pistons are shown away or out of contact with the impacting member;

FIGURE 2 depicts the same embodiment as does FIG- URE 1, but shows the pistons contacting the impact member and the latter protruding from the housing;

FIGURE 3 is a view partially in cross section along the longitudinal axis of another embodiment of the present invention;

FIGURE 4 is a fragmentary view in section of an embodiment of the head of this invention;

FIGURE 5 is a fragmentary view showing yet another embodiment of the head of this invention; and

FIGURE 6 is a view, partially in section, along the longitudinal axis of still another embodiment of the present invention.

Referring to FIGURE 1, there is shown an impacting tool denoted by reference numeral 1. This tool is preferably of circular cross section. Within the bore 18 of the housing 3 is slidably mounted a primary piston 2. The interface between piston 2 and housing 3 is preferably fluid tight to avoid the loss of force through the escape of fluid along the interface. A secondary piston 6 is also slidably mounted within the housing 3 in bore 18. The secondary piston preferably has a projection 9 terminating in a cap 16 for contacting impacting member 13 on its cap 15, thrusting the member outwardly from the longitudinal axis of the tool. Biasing means, preferably in the form of a compression spring 4, is interposed between primary piston 2 and secondary piston 6 to force the former away from the impacting member 13. Secondary piston stop 17 terminates the movement of secondary piston 6 when it is under the influence of the spring 7. Buffer means 19, preferably in the form of a compression spring, is interposed between the primary piston 2 and the buffer spring retainer 20. Head 10 is threadedly engaged in a structural member 8 which in turn is secured in the housing 3. Within the head 10 is secured a sleeve 11 fixed in position by a set screw 12. Slidably mounted in sleeve 11 is the impacting member 13, biased inwardly by compression spring 14, and retained within the sleeve by the shoulder of the cap 15. Forward exhaust port 23 functions to allow air to escape from the bore 18 as primary piston 2 moves away from the impacting member 13 by action of the springs 7 and 4. Reverse exhaust port 5 is positioned within the housing 3 to allow the escape of air as the pistons move towards the impacting member 13. This port also serves to avoid the creation of a vacuum within the bore between the piston 6 and the structural member 8 when the piston is moving away from the impacting member. The primary piston 2 is forced against the secondary piston 6 which in turn is forced against the impacting member 13 preferably by the action of air pressure within bore 18 from a compressed air source 21, admitted through a standard valve 22 which is activated by the operator of the tool. In order to avoid uncoupling the valve 22 from the housing, preferred practice dictates the use of a flexible hose to couple the two. The hose also provides greater flexibility in operation by allowing control of the air apart from control of the tool.

FIGURE 2 depicts the same embodiment shown in FIGURE 1 and hence the reference numerals refer to identical parts. The purpose of FIGURE 2 is to illustrate the distended position of impacting member 13 forced by secondary piston 6 and primary piston 2 when these pistons are in the position shown. As indicated previously, the impacting member 13 is thrust outwardly by the action of air pressure on one end of the primary piston 2 through the chain of elements described.

FIGURE 3 illustrates another embodiment of the impact tool of this invention shown in general by reference numeral 31. In this embodiment only one piston 32 is employed. Piston 32 is biased away from the impacting member 43 by means of a tension spring 49. This spring is secured at one end to piston stop 50 which also functions to arrest the movement of the piston when it is moving away from the impacting member 43. In order to absorb the considerable shock experienced on the impact of the piston 32 against structural member 38, a shockabsorbing bushing 36 may be provided. As in the previously described embodiment of this invention, the impacting portion of piston 32 is in the form of a long projection 39. Housing 33 has a forward exhaust port 30 and reverse exhaust port 35, which serve the same purpose as the corresponding exhaust ports in FIGURES 1 and 2. For convenience of construction, head 40 is threadedly secured to structural member 38, which in turn is fixed within the housing 33. The impact member 43, here shown in distended position, is received within sleeve 41, which is secured by set screw 42. When the piston 32 moves away from the impacting member 43, the latter is urged inwardly by means of compression spring 44. Upon the admission of air pressure to bore 48, the piston 32 through its rounded end 46 contacts a similarly rounded end 45 in the form of a cap on impacting member 43. This cap has a shoulder which acts as a keeper against the impacting member being driven from the tool.

FIGURE 6 shows still another embodiment of the instant invention. The impact tool, preferably of circular cross section, is shown generally by reference numeral 71. Within the bore 88 of housing 73 are slidably disposed primary piston 72, secondary piston 76 and a third piston 79. The midsection of the secondary piston 76 is tapered, the tapered portion being received by the corresponding tapered portion 87 in member 78. Tapered portion 87 thus forms a stop for the scondary piston 76. The third piston 79, similarly, has a tapered midsection for reception by a corresponding tapered portion 86 in the head 80; the tapered portion 86 functions as a stop for the third piston. Compression springs 74 and 77, as in the previously described embodiments, serve to bias the primary and secondary pistons away from and to arrest these pistons as they move towards the impacting member 85. The reverse exhaust port 75 and forward exhaust port 89 perform the same functions as the corresponding exhaust ports previously described. Spherical ball 81 floats freely within the housing 80 and serves to tansmit force from the third piston 79 .to the impacting member 85. The impacting member is slidably received within sleeve 82 which, in turn, is secured within head 80 by set screw 83. Compression spring 84 urges the impacting member 85 inwardly towards the longitudinal axis of the housing 73. Buffer spring 90, as before, servesto cushion the impact of the primary piston 72 as it moves away from the impacting member. By providing the additional piston 79, it is possible to evenly transmit, along the housing of the impact .tool, the considerable force imposed on the housing 73 and its head 80 by piston imi pact; the force being .distributedby means of stops 86 and87.

FIGURES '4 and 5 show alternate embodiments of means for converting longitudinal force to lateral force. Element 53 is a modified head for the scondary piston previously described-with reference to FIGURES l and 2 It is to be understood, of course, that this head'could be similarly adaptable to the embodiments shown inFIG- URES 3 and 6. The head is wedge-shaped with its inclined face 54 facing cap 55 of theimpacting' member 56. As the wedge is thrust towards the impacting member, the inclined face 54 contacts the cap 55 and forces the contacting member 56 outwardly. In FIGURE 5, instead of a wedge-shaped head there is shown a floating sphere 58 which is contacted by extension 57 of a piston partially shown. As the extension 57 moves towards the impacting member 59, the surface of the sphere contacts the rounded surface of the inpacting member thrusting it outwardly. The use of a freely floating sphere has the advantage of increasing the wear area over that otherwise available. Motion of the various elements is indicated by the arrows.

FIGURES 4 and 5 also illustrate displacement of head 53 and projection 57 from the longitudinal axes of their housings. This location affords a maximum impacting member length for a given housing radius while assuring that the member is within the housing except when contacted by the secondary piston.

Various other direct means of converting longitudinal motion to lateral motion will occur to those skilled in the art. It is important, however, that this conversion be accomplished directly and not through the means of a bell crank or other mechanism which requires a pivot for their operation. It has been found that a pivot or pin is subject to failure in shear upon repeated action of the tool. Moreover, the use of a bell crank system for translating motion sufiers because it requires a larger cross-sectional area than is required by this invention.

The impacting member is preferably disposed at an angle of about 60 to the longitudinal axis of the housing. At this angle, the impact tool can easily be placed in restricted working areas, for example, between the inside and outside panels of an automobile door, and yet be in a position for the axis of the impacting member to the normal to a workpiece.

The tip of the impacting member may be of any configuration desired. In automotive repair work, the preferred shape is hemispherical as is indicated by reference numeral 24 in FIGURES 1 and 2. However, the tip may be cone-shaped as shown in FIGURE 4 by reference numeral 60 for certain applications.

The operation of this invention will be described with reference to FIGURES l and 2. The at-rest or neutral state of the activating means is shown in FIGURE 1. As was previously described, these means comprise the primary piston 2 and the secondary piston 6. When it is desired to have impacting member 13 strike a workpiece, an operator opens valve 22 to admit air into the bore 18. The tool is sufiiciently responsive to allow an operator to actuate the tool at rapid rate. In this connection a button. activated air valve would prove helpful. The air, which is under considerable pressure, thrusts the primary piston'2 against the secondary piston 6. The secondary piston then moves towards the impacting member contacting it at the interface between the projection 9 and the cap 15, driving it sharply outward. This position is shown in FIGURE 2. Upon the release of the air pressure, air will escape through the forward exhaust port 23, allowing compression spring 4 to push the piston 2 away from .the secondary piston 6 and the impacting member 13. Compression spring 7 also acts to force secondary piston 6 away from the impacting member 13. When the projection 9 begins to move away from the impacting member 13, spring 14 urges the latter inwardly towards the center line "of the-.tool. As the primary piston 2. moves away from the impacting member 13 air escapes from the forward exhaust portv 23 and the shock of the piston is arrested by buffer spring 19. Similarly, as the pistons 2 and 6 move away from the impacting member, reverse exhaust port 5 admits air to the space being developed in the annular cavity between the large portion of the secondary piston and the impacting member. This avoids the creation of a vacuum which would otherwise retard the movement of the pistons. When the device is actuated to thrust the impacting member outwardly, the reverse exhaust port 5 acts to allow air to escape from the annular space thus avoiding the dissipation of energy which otherwise would be required to compress air. When another impact is desired, the cycle is repeated.

While the present invention has been described with reference to certain preferred embodiments, the scope of the appended claims should not be limited thereto for minor variations will occur to those skilled in the art. For example, in some applications the motive force for driving the pistons towards the impacting member could be a solenoid-operated plunger.

What is claimed is:

1. An impact tool comprising:

(a) a relatively long, narrow and rigid housing having a bore;

(b) a head rigidly aflixed to one end of the housing;

(c) an impacting member having a cap and a tip, the impacting member being disposed within the head at an angle to the longitudinal axis of the housing and operable to move to extend its tip laterally outside the head;

(d) means for retaining the impacting member with the head;

(e) piston means slidably disposed in the bore for linear movement toward and away from the impacting member, the piston means being operable to directly strike the cap of the impacting member to drive the tip laterally outside the head;

(f) spring means for biasing the piston means away from the impacting member; and

(g) means for driving the piston means towards the impacting member to strike the cap and drive the tip laterally outside the head.

2. An impact tool comprising:

(a) a relatively long, narrow and rigid housing having a bore;

(b) a head rigidly affixed to one end to the housing;

(c) a straight impacting member having a cap and a tip, the impacting member being disposed within the head at an angle to the longitudinal axis of the housing and operable to move to extend its tip laterally outside the head;

(d) means for retaining the impacting member within the head;

(e) piston means slidably disposed in the bore for linear movement toward and away from the impacting member;

(f) a substantially spherical ball disposed between the cap of the impacting member and the piston means in position to be directly struck by the piston means and in turn to strike the cap of the impacting member to drive the tip laterally outside the head;

(g) spring means for biasing the piston means away from the impacting member; and

(h) means for driving the piston means towards the impacting member to strike the spherical ball and drive the tip laterally outside the head.

3. The impacting tool claimed in claim 2 wherein the piston means includes:

(a) a primary piston slidably disposed within the bore;

(b) a secondary piston slidably disposed within the bore between the impacting member and the primary piston, the secondary piston having a tapered 7' 8 portion on the side opposite the primary piston, the References Cited" housing having a complementary tapered portion Op- UNITED STATES PATENTS 1 erable to cooperate with the tapered portion of the I 1 I 1 secondary piston to stop the secondary piston in its 1 335 5; movement toyvards the impacting member; 5 2,694,435 11/1954 Lund r 173-4121 (c) a compresslon sprfng w the PQm y P Q 2 720 02 10/1955 Geller and the secondary piston disposed to bras these pls- 3,286,558 9 Hufnagel 3 tons away from each other as they move towards the 3,326,303 6/ 1967 Jones 173 -1 2 impacting member; and s i (d) a third piston disposed between the secondary pis- 10 DAVID BROWN i r Examm'er' i ton and the impacting member in position to strike R MATTERN, Examiner the spherical ball. L. P. KESSLER, Assistant Examiner;