Curved surface rubbing apparatus

A polishing apparatus in which one of two workpieces to be polished or abraded which contact each other at respective arcuate or spherical surfaces, is placed on a fixed base and turned or fixed in a horizontal plane with the other workpiece held under pressure by a retainer provided on a gate type frame which can be swung around the center of curvature of the contact surfaces of the two workpieces by a swinging unit capable of varying the range of swinging movement of the gate-type frame. The center of the swinging movement of this frame can be varied by changing the position of two pivot-connected block units vertically in a stepless manner and the position of the retainer to a reference axis can be varied. This enables the apparatus to be applied to workpieces having arbitrary curved surfaces to be polished and of different dimensions.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus for rubbing two members, which 
contact each other at their spherical or arcuate surfaces, against each 
other to polish the same, and more particularly to a curved surface 
rubbing apparatus used for the maintenance and repairing of the parts of a 
construction machine. 
2. Description of the Prior Art 
The devices and machines having spherical contact members therein include a 
mechanical seal, a hydraulic pump and a hydraulic motor. 
For example, the spherical contact surfaces of a cylinder block and a valve 
plate in a hydraulic pump, or the similar surfaces of a cradle and a 
rocker cam therein become rough or are worn non-uniformly while they are 
used for a long period of time, to cause the performance of the pump to be 
deteriorated. 
Especially, it has been demanded that these surfaces have a higher accuracy 
so as to cope with the recent increase of the pressure used in the 
above-mentioned kind of devices, and the time and labor required to carry 
out the maintenance work for these surfaces tends to increase. 
In addition, such spherical contact members produced by various 
manufacturers have various sizes and curvatures and are a large number of 
types, so that the maintenance work for these members becomes increasingly 
inefficient. 
SUMMARY OF THE INVENTION 
Object 
An object of the present invention is to provide a curved surface rubbing 
apparatus capable of being applied to spherically contacting members of 
various radii of curvature, and polishing the contact surfaces thereof 
efficiently by rubbing them against each other to obtain very high 
curvature accuracy. 
Structure 
The apparatus of the present invention consists of a means for fixing or 
turning in a horizontal plane a first member of the two members which 
contact each other at their curved surface, a gate type frame which holds 
under pressure from the upper side a second member surface contacting the 
first member, and which is linked to a swinging unite, fixed support posts 
set up firmly in opposition to a pair of leg members of the gate type 
frame, and a pair of units of pivot-connected blocks, each of which units 
is composed of two blocks connected at their respective intermediate 
portions to each other by a pivot and engaged with a corresponding leg 
member and fixed post, so that the vertical position of the blocks can be 
regulated freely, the gate type frame is swung with the pivot-connected 
blocks positioned at the center of curvature of the contact surfaces of 
the first and second members.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A reference numeral 1 denotes a valve plate, which constitutes a first 
member, of a hydraulic pump, and 2 a cylinder block constituting a second 
member, the radius of the curved contact surfaces 3 of these two members 
being 300-500 mm. 
A reference numeral 4 denotes a turntable supporting and adapted to turn 
the first member, and a fixed base 5 is provided therein with a variable 
speed motor 6, a speed reducer 7 and a vertical transmission shaft 8. 
The reference numerals 9a, 9b denote fixed support posts set up on both 
sides of the fixed base, and 10 a gate type frame in which leg members 
10a, 10b, arranged in parallel with the outer side surfaces of the fixed 
support posts, are connected together by a top plate 11, on which a 
pressure cylinder 12 is provided. 
A reference numeral 13 denotes a reinforcing member, a pair of retainer 
members 14 hold both sides of the second member and are adapted to be 
positioned along slide bars 15, using positioning nuts 16. 
A reference numeral 17 denotes a cylinder rod, and 18 a chuck applying a 
required level of pressing force constantly to the second member. 
A reference numeral 20 denotes pivot-connected block units, each of which 
includes two C-shaped blocks 22, 23, as shown in FIG. 3, which support 
both end portions of a pivot 21 so that the pivot can be turned, and which 
are engaged with the corresponding fixed support post 9 and leg member 10 
so that the blocks 22, 23 can slide in a stepless manner. Fixing means 24, 
25 are provided, consisting of nuts by which the blocks 22, 23 are 
adjustably to their individual support post 9 and leg member 10 in which 
different positions upwardly of the base. 
It is preferable that the side surfaces of the fixed support posts 9 and 
leg members 10 be provided with V-shaped recesses in which the front end 
portions of the nuts are to be fitted. 
The graduations, not shown, for use in positioning the pivot-connected 
block units are accurately in different positions as shown in phantom in 
FIG. 1, are also provided. A reference numeral 21a denotes a spacer. 
The pivot-connected block units 20 are fixed with regard to the center of 
the arc of the contact surface 3 of a workpiece so that the contact 
surface 3 is swung about that center as described herein. 
A reference numeral 26 denotes a swinging unit 27 a variable speed motor, 
27a a rotational directions converter, 28 a transmission shaft, 29 rotary 
discs, and 30 rod guides fixed to the discs 29. Direction of rotation 
changes of the discs 29 is effected by the converter 27a. 
A reference numeral 31 denotes swingable rods provided symmetrically with 
respect to the leg members 10a, 10b. One end portion of each of the 
swingable rods 31 is joined to the corresponding leg member by a bolt 31a 
insertable into on of a plurality of bolt holes 32 provided in the leg 
member, and the other end portions thereof is supported on the 
corresponding rod guide, the intermediate portion of the swingable rod 31 
is joined to an annular member 33 positioned between left and right shock 
absorbing springs, 34, 35 provided in the rod guide 30. 
Each of the rod guides 30 is fixed to the relative disc 29 so that the 
distance between the rod guide and the center of the disc 29 can be 
varied, whereby the range of a swinging movement of the gate type frame 
can be varied. The swinging unit 26 as a whole is adapted to be moved 
vertically and set using set screw 37 in a selected position with respect 
to the fixed base by a slide guide 36. 
When fixing position 31a of the swingable rods 31, the fixing position of 
the rod guides 30 with respect to the rotary discs 29 and the height of 
the swinging unit with respect to the fixed base are set suitably, the 
swinging angle and the swinging range (for example, a symmetric or 
asymmetric range with respect to a vertical axis) of the leg members 10a, 
10b, i.e. gate type frame 10 can be varied. 
In the above-described apparatus, the first member or workpiece 1 is swung 
around the center of its curved contact surface within a range of angles 
set by the swinging unit. Accordingly, the contact surfaces of these 
workpieces are displaced wholly and polished owing to the effect of 
abrasives as these members are rubbed against each other. If the first 
member is fixed, the polishing of an arcuate surface can be done. 
The center of such a swinging movement, i.e. the position of the 
pivot-connected block units 20 can be varied freely along the fixed 
support posts and leg members. Therefore, the rubbing and polishing of 
members or workpieces having complementary concave and convex curved 
surfaces consisting, for example, of a cradle and a rocker cam as first 
and second members, respectively, shown in FIG. 5, can also be done. 
The apparatus according to the present invention can thus be applied in a 
stepless manner to members the contact surfaces of which have various 
curvatures and various curved condition. Therefore, it has a wide range of 
applications and permits a position regulating or changing operation to be 
carried out easily, so that the apparatus has a high operation efficiency. 
Owing to these characteristics, curved contact surfaces with a sufficiently 
high curvature accuracy can be obtained during the maintenance and 
repairing of a device having curved contact surfaces, in a short period of 
time without using any man power.