Seal Assembly Tool

Abstract

A tool for facilitating the assembly of a dust boot or seal with the cylinder and piston of a caliper disc brake actuator, comprising a pair of allochirally arranged bars pivoted together to define relatively long handle sections and relatively short distal sections, the distal sections carrying mating plates shaped as part-circular arcs, the plates being arranged to define an oval when their distal tips are in contact and to lie in a common circle when their tips are separated, the plates being formed with external grooves lying in a plane perpendicular to the axis of such common circle and adapted to receive an internal bead at the proximal end of such a boot for radially expanding and longitudinally extending the boot, and resilient means resisting separation of the plates.

Description

The present invention relates to an applicator tool for facilitating the installation of a seal or boot between the open end of a cylinder and the outer end of a piston reciprocable in the cylinder; and the primary object of the invention is to provide a novel tool specifically designed to perform that function. Further objects of the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, our invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is an exploded, somewhat diagrammatic longitudinal section of a caliper housing for a known power disc brake assembly, a piston for cooperation therewith and a known form of boot;

FIG. 2 is an enlarged, fragmentary section through such a boot;

FIG. 3 is a section similar to FIG. 1, showing the piston partially entered in the cylinder and showing our tool in use in an intermediate stage of manipulation to make the operative connection between the boot and the piston;

FIG. 4 is a similar section, showing the parts fully assembled;

FIG. 5 is an elevation of our improved tool; and

FIG. 6 is a section taken on the line 6--6 of FIG. 5.

Referring more particularly to the drawings, it will be seen that we have illustrated a conventional caliper housing 10 formed to provide a cylinder 11. Near the open end of the cylinder, there is provided an inwardly-opening peripheral groove 12 and between the groove 12 and the open end of the cylinder is provided a further internally opening groove 13. Conventionally, an O ring or similar packing 14 is installed in the groove 12. According to conventional practice, a seal or boot 15, formed of soft, flexible and elastic rubberoid material, is installed between the cylinder 11 and a piston 16 adapted to be mounted for reciprocation in the cylinder 11. Said piston is conventionally formed with a peripheral outwardly opening groove 17 near its trailing end.

The configuration of the boot 15 is illustrated in FIG. 2. As shown, it has an external bead 18 at one end for snug reception in the groove 13, whereby that end of the boot is anchored with respect to the casing 10. An outturned section 19 merges with a substantially cylindrical body portion 20 which, in turn, merges with an inwardly and axially rolled section 21 which terminates in an internal peripheral bead 22 proportioned and designed for reception in the groove 17 of the piston 16. It will be apparent that, since the bead 22 must have a significantly smaller diameter than does the bead 18, difficulty will be encountered in entering the piston 16 past the bead 22 without rolling the portion 20, 21, 22 axially inwardly. It is to overcome that difficulty that we have devised the tool of the present disclosure.

The tool is best illustrated in FIGS. 5 and 6 wherein it is generally designated by the reference numeral 23. The tool comprises allochirally arranged bars 24 and 25 each having a handle portion 26 or 27 and a shorter, distal portion 28 and 29. The bar 24 is provided with arms 30, 31 while the bar 27 is provided with arms 32, 33 so spaced as to be received between the arms 30 and 31 when the two bars are brought into facing relation. The arms are perforated for the reception of a pivot 34, and a coiled spring 35 is wrapped about the pivot 34 and comprises arms 36 and 37 extending, respectively, into contact with the handle portions 26 and 27 to bias the handle portions away from each other and the distal portions 28 and 29 toward each other.

Suitably secured, as by welding, for instance, to the distal regions of the tool are mating, arcuate plates 38 and 39. Each of these plates is part circular but somewhat less than semi-circular so that, when their distal regions are in contact under the influence of the spring arms 36 and 37, the mating plates define an oval figure. However, when the handle portions 26 and 27 are pressed toward each other against the tendency of the spring 35, the plates 38 and 39 will be separated so that they may lie in a common circle slightly larger than the outside periphery of the piston 16.

As is most clearly shown in FIGS. 3 and 6, the axial dimension of the plates 38 and 39 tapers from their ends nearer the sections 28 and 29.

At or near its end remote from the taper, each plate 38 or 39 is formed with a peripheral, outwardly opening groove 40, the cross-section of which closely approximates the cross-section of the groove 17 of the piston 16.

In use, the ring or seal 14 is installed by hand. Then, the bead 18 is manually tucked into the groove 13. Now, with the plates 38 and 39 in their solid line position of FIG. 5, the rolled portion 21, 22 of the boot 15 is rolled outwardly and the bead 22 is slipped over the forward end of the tool 23 and worked into the groove 40. Preferably, the interior surface of the boot and the exterior surface of the tool will be somewhat lubricated with, for instance, conventional brake fluid.

At this time, the tool orifice will be substantially in register with the open end of the cylinder 11. Now, the handle portions of the tool will be squeezed to expand the orifice between the plates 38 and 39, thereby likewise expanding the left-hand end portions of the boot 15. The piston 16 is then introduced through the tool orifice and into sealing engagement with the ring 14. The tool is now moved toward the left completely to straighten the rolled portion 21 of the boot and, in some cases, to stretch the elastic boot longitudinally, care being taken not to dislodge the bead 18. When the right-hand extremity of the plates 38 and 39 has passed the groove 17 in the piston, (or the piston has been manually moved to the right to cause the groove 17 to pass the plate extremities) then the bead 22 will snap or be worked off the end of the tool and will enter the groove 17 to complete the assembly of the boot between the cylinder and the piston.

Now, that the tool has been completely released from the boot, the boot will tend to return to the equilibrium position illustrated in FIG. 2, thus drawing the piston 16 more deeply into the cylinder 11, as indicated in FIG. 4.

Claims

1. For use with a power disc brake cylinder having an open end with an inwardly-opening peripheral groove near said open end and spaced axially outwardly from said cylinder open end and partially obstructing access to said open end, an outboard shoe support bracket formed integrally with said cylinder, a piston for reciprocation in said cylinder and insertable through said open end, said piston being formed with an outwardly-opening peripheral groove near its proximal end, and a sealing gasket including an external peripheral bead at one end receivable in said first-named groove, and an internal peripheral bead at its other end receivable in said piston groove; the invention which consists of a pair of allochirally related bars, each having a handle portion and a distal portion, means pivotally connecting said bars together so that movement of said handle portions toward each other separates said distal portions, and each of said distal portions being part-circular and having a peripheral extent slightly less than 180.degree. and being formed to provide an outwardly opening, peripherally coextensive groove for receiving said internal bead, means resiliently biasing said handle portions away from each other, and the inner surfaces of said distal portions, when separated to a predetermined degree, lying in a common circle having a diameter slightly exceeding the outer diameter of said piston whereby said piston may be axially entered through the orifice defined by said distal portions.