Montgomery County Police Chief Robert J. diGrazia yesterday announced a sweeping reorganization of his police force.

With the backing of County Executive James P. Gleason, diGrazia ousted two high-ranking officers, consolidated major divisions within the department, and proposed a redefinition of almost all interdepartmental ranks.

In a rapid series of moves that left many police officers stunned diGrazia ordered Major Robert M. Sigwald, 48, chief of the department's patrol division, to clear out his desk by the day's end, and told Major Donald E. Brooks, 50, technical services bureau chief, that his services would not be needed after Sept. 1.

Sigwald's position, which placed him in command of virtually all on-the-street policemen, was eliminated outright as part of the consolidation of police divisions, while Brooks' department is being expanded and eventually will be headed by a civilian.

The purpose of all the reshuffling according to Gleason, is to "make the department more community-oriented" - the same mandate he had given diGrazia when he hired the former Boston police chief last fall.

Gleason had for several years expressed private dissatisfaction with what he regarded as a militaristic department that kept unnecessarily aloof from the community it policed.

Sources within the department said yesterday that Major Sigwald was of that old spit'n'polish school, although his tough-mindedness won him the sometimes grudging respect of his men. That same tough-mindedness apparently put him continually at odds with diGrazia and the new chief's plans for the department, sources said.

Sigwald was put on administrative leave yesterday, effective immediately, and will be forced to retire in two weeks, after almost 26 years on the force.

Major Brooks will be forced to retire at the end of August, with his place at the head of the new Management Services Bureau of the force to be taken by a civilian. These moves will reduce from four to two the number of majors on the force. The second-ranking lieutenant colonel's post was abolished soon after diGrazia took over.

County officials maintain that the changes are consistent with diGrazia's past expressions of concern that the rank-and-file officers are ignored and lines of authority within the department too long. As a result of the changes, Gleason said that more power will be delegated to officers closer to the patrolman-in-the-street, and the patrolman himself will have more opportunities for advancement.

"We've lost touch with the working cop out on the streets," diGrazia said yesterday. "That's 80 per cent of the department. For too long we've ignored the guy at the working level.

These same moves, diGrazia maintained, will help bring the department closer to the community it serves because commanders of the department's four regional county stations will have direct involvement with their localities and be correspondingly more responsive.

"We're not involved with the community as much as we should be," he said.

As part of the changes announced yesterday, five major divisions are being consolidated into three new ones. The new field operations division will have responsibility for patrols and communications; investigative services will handle criminal investigations and juvenile crime; and management services will be responsible for financial management, accounting, supplies, and community services.

At present, the department is divided into the patrol division, the special operations division - covering such areas and traffic enforcement and crime prevential - the criminal investigation division, the administrative services bureau, which runs the police training academy, and the technical services bureau - which handles such things as supplies and records.

Along with consolidating department functions, diGrazia's plan also expands the number of ranks a patrolman can aspire to and removes barriers that currently limit the number of patrolmen who can hold any one rank at any one time.

As for the higher rank categories, such as sergeant, lieutenant, captain, and major - the number of grade has been increased to allow for some promotions based solely on merit. Currently, all rank advancement in these categories is based on competitive exams, but under the new program two of the ranks will be rewarded only on

This proposed revamping - requiring changes in job descriptions and adding some new positions - will require the approval of the country's personnel board, a group that in the past occasionally has stood in the way of personnel and job changes as proposed by Gleason and the chief administrative officer.

There was considerable feeling among officers contacted yesterday that morale had been hurt, not helped as Gleason and diGrazia maintained - by the suddenness of the action and the preemptory dismissal of Majors Sigwald and Brooks.

"There's no security in this job - not with a man like him in there," said one patrolman who asked not to be identified. "He's going to cut out all the people who stand in his way . . . We're already calling this Black Monday."

The same officer added, "(Sigwald and Brooks) deserve something after being there 25 years - not just getting kicked out on their ass."

Another low-ranking officer noted that although he objected to the way Sigwald was treated, "the overall objective is good . . . The department's been top-heavy for several years."

The policeman, who also asked not to be identified, noted that the department already had been suffering from a drop in morale since diGrazia came. Several weeks ago, the Montgomery County Police Association had complained that diGrazia was preoccupied with patrolmen, and giving short shrift to other officers and their functions.

"There's been a general malaise since he's been here; people are on edge, wondering what he's going to do," the officer said. "Now he's started to put his cards on the table. It's been a long six months when you're sitting and waiting."